Hash marks

Hash marks are short lines, running perpendicular to sidelines or sideboards, used to mark locations, primarily in sports.

Usage in ice hockey

In ice hockey, the hash marks are two pairs of parallel lines on either side of the face-off circles in both ends of the rink. Players must remain on their team's side of the hash mark nearest their own goal during a face-off until the puck hits the ice.

Usage in gridiron football

KentAkron (cropped)
...at Dix Stadium (above)

In US football and Canadian football, the hash marks are two rows of lines near the middle of the field that are parallel to the side lines. These small lines (4-inches wide by 2-feet long) are used to mark the 1-yard sections between each of the 5-yard lines, which go from sideline to sideline. All plays start with the ball on or between the hash marks. That is, if the ball is downed in between a hash mark and the nearest sideline, it must be placed on that hash mark for the next play.

Prior to the adoption of hash marks (which were first utilized at the first NFL playoff game in 1932), all plays began where the ball was declared dead, including extra point attempts.

The hashmarks in that indoor 1932 playoff game were originally 10 yards from the sideline, and that width was adopted by the NFL for the 1933 season. It was increased to 15 yards (70 feet apart) in 1935, 20 yards (40 ft apart) in 1945, and to the current 23 yards, 1 foot, 9 inches (18½ ft apart) in 1972.[1]

In most forms of professional football in the U.S., including the National Football League and most forms of indoor football, the hash marks are in line with the goal posts, both being 18 feet 6 inches apart in the NFL and between 9 and 10 feet in indoor football. High school football, college football and Canadian football have hash marks significantly wider than the goal posts. The college football standard, which was the previous standard in the NFL (19451971), is 40 feet apart, (20 yards from the sidelines)[2] introduced in 1993.[3][4] Previously, the college width was the same as the high school standard, at one-third of the width of the field (53​13 feet).

The Canadian standard is 51 feet in width, 24 yards from each sideline. A Canadian football field width is 65 yards (195 feet), 35 feet wider than those in the United States.[5]


  1. ^ "Owners give offense big seven-yard boost". Rome News-Tribune. Georgia. Associated Press. March 24, 1972. p. 6A.
  2. ^ "High On The Hash". Sports Illustrated. (CNN). August 28, 1972.
  3. ^ Chaptman, Dennis (March 26, 1993). "Moving hash marks should open offenses". Milwaukee Journal. p. C2.
  4. ^ Clark, Bob (September 2, 1993). "New rules to keep coaches on toes". Eugene Register-Guard. Oregon. p. 9F.
  5. ^ "CFL Official Playing Rules 2011" (PDF). Canadian Football League. pp. 8, 12. Archived from the original (PDF) on 11 May 2012. Retrieved 5 August 2013. The field shall be 110 yards long by 65 yards wide [...] Twenty-four yards in from each sideline each 5-yard stripe shall be marked by a short cross stripe parallel to the sidelines (Hash Marks).
1932 NFL Playoff Game

The 1932 NFL Playoff Game was an extra game held to break a tie in the 1932 season's final standings in the National Football League. It matched the host Chicago Bears and the Portsmouth Spartans. Because of snowfall and anticipated extremely cold temperatures in Chicago, Illinois, it was moved indoors and played at the three-year-old Chicago Stadium on December 18 on a reduced-size field on Sunday night.

89th Grey Cup

The 89th Grey Cup (Canadian Football League championship) was held in 2001 in Montreal. The Calgary Stampeders claimed their fifth championship in team history with a 27–19 win over the East Division champions and heavily favoured Winnipeg Blue Bombers.

American football field

The rectangular field of play of American football games measures 100 yards (91.44 m) long between the goal lines, and 160 feet (48.8 m) (53 1⁄3 yards) wide. In addition, there are end zones extending another 10 yards (9.144 m) past the goal lines to the "end lines", for a total length of 120 yards (109.7 m). When the "football field" is used as unit of measurement, it is usually understood to mean 100 yards (91.44 m), although technically the full length of the official field, including the end zones, is 120 yards (109.7 m).

White markings on the field identify the distance from the end zone. Inbound lines, or hash marks, are short parallel lines that mark off 1 yard (0.91 m) increments. In most forms of professional football in the U.S., including the National Football League and most forms of indoor football, the hash marks are in line with the goal posts, both being 18 feet 6 inches apart in the NFL and between 9 and 10 feet in indoor football. High school football and college football fields have hash marks significantly wider than the goal posts. The college football standard, which was the previous standard in the NFL from (1945 to 1971), is 40 feet apart, (20 yards from the sidelines) introduced in 1993. Previously, the college width was the same as the high school standard, at one-third of the width of the field (53​1⁄3 feet). Yard lines, which can run the width of the field, are marked every 5 yards (4.6 m). A one yard long line is placed near each end of the field; this line is marked at the center of the two-yard line in professional play and at the three-yard line in college play; this is to denote the line of scrimmage for a point after touchdown kick (the NFL moved up the line of scrimmage for such kicks to the 15-yard line in 2015, but the dash is still there to denote the line of scrimmage for a two-point conversion). Numerals that display the distance from the closest goal line in multiples of ten (up to the 50 yard line) are placed on both sides of the field every ten yards, with arrows right by the numerals to indicate the closer goal line; some fields may denote the goal line with a "G". Weighted pylons are placed on the inside corner of the intersections of the sidelines, goal lines, and end lines. Including the end zones, the total area of an American football field is 57,600 square feet (5,350 m2).

The goalposts are located at the center of the plane of each of the two end lines. The crossbar of these posts is 10 feet (3.048 m) above the ground, with vertical uprights at the end of the crossbar 18 feet 6 inches (5.64 m) apart for professional and collegiate play and 23 feet 4 inches (7.11 m) apart for high school play. The uprights extend vertically 35 feet on professional fields, a minimum of 10 yards on college fields, and a minimum of ten feet on high school fields. Goal posts are padded at the base, and orange ribbons are normally placed at the tip of each upright.According to the high school rulebook recommendations, the field should be angled at approximately 1.2° (rising ​1⁄4 inch per foot, or 1 in 48) upward from each sideline to the center of the field so that the center is 20 inches (51 cm) higher than the sidelines.

Conversion (gridiron football)

The conversion, try (American football, also known as a point(s) after touchdown, PAT, or extra point), or convert (Canadian football) occurs immediately after a touchdown during which the scoring team is allowed to attempt to score one extra point by kicking the ball through the uprights in the manner of a field goal, or two points by bringing the ball into the end zone in the manner of a touchdown.

Attempts at a try or convert are scrimmage plays, with the ball initially placed at any point between the hash marks, at the option of the team making the attempt. The yard line that attempts are made from depends on the league and the type of try or convert being attempted.

If the try or convert is scored by kicking the ball through the uprights, the team gets an additional one point for their touchdown, bringing their total for that score from six points to seven. If two points are needed or desired, a two-point conversion may be attempted by running or passing from scrimmage. A successful touchdown conversion from scrimmage brings the score's total to eight.

Whether a team goes for one or two points, most rules regarding scrimmage downs, including scoring touchdowns and field goals, apply as if it were a normal American fourth-down or Canadian third-down play. Exceptions, including cases where the defense forces a turnover during a conversion attempt, vary between leagues and levels of play. One thing that sets the try apart from other plays in the NFL is that, apart from the actual points, ordinary statistics are not recorded on the try as they would be on a regular scrimmage play. For example, on December 4, 2016, Eric Berry of the Kansas City Chiefs made an interception on a try and physically returned it 99 yards for a defensive two-point conversion. However, because it occurred on a try, Berry did not get statistical credit for the 99 yards of return yardage; nor would a player ever be credited with passing, rushing, or receiving yardage on a try.

Dale Hackbart

Dale Leonard Hackbart (born July 21, 1938) is a former American football defensive back who played twelve seasons in the National Football League for the Green Bay Packers, Washington Redskins, Minnesota Vikings, St. Louis Cardinals, and Denver Broncos from 1960 to 1973. He also played in the Canadian Football League for the Winnipeg Blue Bombers in 1964 and 1965.

Hackbart initially focused on baseball. He spent a season playing baseball for the Grand Forks Chiefs; a Class C minor league team in the Pittsburgh Pirates organization. Bud Grant convinced Hackbart to drop baseball and concentrate on a career in the National Football League.Hackbart was drafted by the Minnesota franchise in the inaugural 1960 American Football League Draft as a quarterback and "territorial selection." He was drafted in the fifth round of the 1960 NFL draft as a generic "back" by the Packers. As Minnesota would never play in the AFL (the group instead joined the NFL as the Minnesota Vikings), Hackbart joined the Packers. Hackbart would eventually join the Vikings in 1966, by this point solely as a defensive back.

In 1973, Hackbart was involved in an on-field transgression that he eventually took to court. He asserted that a late hit by Cincinnati Bengals running back Boobie Clark was an intentional tort.

He was with the Denver Broncos and was their starting safety in 1973.

In the first 1973 regular season game against the Cincinnati Bengals Hackbart's neck was fractured. "It was just before halftime and the Bengals had the ball at around the 45 yard line going in. Boobie Clark came out of a split backfield and ran down the hash marks. I was playing free safety so I dropped back to the center of the field. The ball went up in the air and I converged into the endzone. Billy Thompson, who was playing left corner for the Broncos, jumped in front of me and Boobie Clark and intercepted the pass. I tried to block Boobie and landed on the ground. When I came up on to one knee watching Thompson run the ball, Boobie came up from behind me and whacked me in the back of the head, with a right fore-arm and drove me into the ground, after the Play was finished. My left arm went numb ! At halftime in the locker room I couldn’t take off my helmet so I was packed in ice around my neck and helmet." Hackbart did not at the time report the happening to his coaches or to anyone else during the game. However, because of the pain which he experienced he was unable to play golf the next day. He did not seek medical attention, but the continued pain caused him to report this fact and the incident to the Bronco trainer who gave him treatment. Apparently he played on the specialty teams for two successive Sundays, but after that the Broncos released him on waivers. (He was in his thirteenth year as a player.) He sought medical help and it was then that X-rays were taken, which revealed that the C4, 5, 6, and 7 vertebrae on his neck were fractured. This injury ended his football career.

In 1974 neurosurgeons told Hackbart that if he didn’t have surgery to repair the damage, he would lose use of his left arm, shoulder, and any muscles involved with the damaged vertebrae. The Broncos claimed they were not liable. Hackbart hired an attorney, Rodger Johnson of Johnson & Mahony, and brought a suit against the Bengals. Hackbart v. the Cincinnati Bengals became a precedent setting case. In the case the courts ruled that in the course of a professional football game an intentional infliction of an injury by one player upon another might constitute a tort.

As a result of the lawsuit, the National Football League mandated that all stadiums had to be equipped with X-ray machines. The head slap maneuver which injured Hackbart was banned. Later, rules against spearing with the helmet and helmet to helmet contact were created. Hackbart settled with the Bengals and the Broncos filed a Workman's Compensation claim which paid for the surgery that was performed in 1976.

The case was eventually appealed to the Tenth Circuit Court of Appeals in 1979 and has become a key point of discussion in several first year law school tort classes. Hackbart v. Cincinnati Bengals, Inc., 601 F.2d 516 (10th Cir. 1979).


A fid is a conical tool traditionally made of wood or bone. It is used to work with rope and canvas in marlinespike seamanship. A fid differs from a marlinspike in material and purposes. A marlinspike is used in: (working with wire rope, natural & synthetic lines, may be used to open shackles), and is made of metal. A fid is used to hold open knots and holes in canvas, and to separate the "lays" (or strands) of synthetic or natural rope for splicing. A variation of the fid, the gripfid, is used for ply-split braiding. It adds a jamming cleat to pull a cord back through the cord split by the fid's point.

Modern fids are typically made of aluminum, steel, or plastic. In addition to holding rope open to assist the creation of a rope splice, modern push fids have markings for precise measurements in a variety of sizes of rope. The length of these fids is typically 21 or 22 times the diameter of rope to be spliced. A half-inch diameter rope would have any accompanying fid 10.5–11" in length with hash-marks denoting the long and short fid measurements. A short fid is ​1⁄3 a fid length and a long fid is ​2⁄3 the overall fid length.

Modern major rope manufacturers such as Yale Cordage, New England Ropes, and Samson Rope Technologies each have full sets of published splicing directions available on their websites. Typically, all splice directions measurements use fid-length as the unit of measurement.

Below is a chart that shows exact measurements of full fid lengths, short fid lengths, and long fid lengths, using 21 times the diameter of the rope.

Flat (gridiron football)

The flat in American and Canadian football is the area of the field extending ten yards into the defensive backfield from the line of scrimmage and extending outside the hash marks to the out-of-bounds lines (a distance of about 15 yards).Offenses will typically exploit the flat in order to neutralize a strong attack from the defensive line in the middle of the field or to manipulate a defense's strong pass coverage farther down field. For example, in flat route plays, quarterbacks pass the ball to a player (often a running back) in the flat in hopes that, while the pass has not gone downfield, the receiver (far from the middle of the field and not far downfield enough to worry about cornerbacks and safeties) will have a clear line for an after-the-catch run. If the quarterback hopes to throw farther downfield, the running back in the flat is an outlet receiver. If the receiver is accompanied by blockers, the play is called a screen pass.

Defenses meanwhile will generally assign a linebacker "flat responsibility" to guard against such passes, but it is difficult to defend against because the offense will usually use the flat route in conjunction with an attack downfield (sometimes as a feint), necessitating a quick linebacker adjustment to make an early tackle against a faster running back after the pass.

The flat, then, denotes one of the many areas of the field over which offensive and defensive coordinators play.


Goalball is a team sport designed specifically for athletes with a vision impairment. Participants compete in teams of three, and try to throw a ball that has bells embedded in it into the opponents' goal. The ball is thrown by hand and never kicked. Using ear-hand coordination, originating as a rehabilitation exercise, the sport has no able-bodied equivalent.

Played indoors, usually on a volleyball court, games consist of twelve-minute halves (formerly ten-minute halves).Teams alternate throwing or rolling the ball from one end of the playing area to the other, and players remain in the area of their own goal in both defence and attack. Players must use the sound of the bell to judge the position and movement of the ball. Eyeshades allow partially sighted players to compete on an equal footing with blind players. Eyepatches may be worn under eyeshades to ensure complete coverage of the eye, and prevent any vision should the eyeshades become dislodged.

The International Blind Sports Federation (IBSA), founded in 1981 and responsible for a range of sports for the blind and partially sighted, is the official governing body for the sport.


Gridiron may refer to:

Gridiron (cooking), a type of cooking grill

Gridiron, Sonora, a steamboat landing on the lower Colorado River after 1854

Hatch mark

Hatch marks (also called hash marks or tick marks) are a form of mathematical notation. They are used in three ways:

Unit and value marks — as on a ruler or number line

Congruency notation — as on a geometric figure

Graphed points — as on a graphHatch marks are frequently used as an abbreviation of some common units of measurement. In regard to distance, a single hatch mark indicates feet, and two hatch marks indicate inches. In regard to time, a single hatch mark indicates minutes, and two hatch marks indicate seconds.

In geometry and trigonometry, such marks are used following an elevated circle to indicate degrees, minutes, and seconds — ( ° ) ( ′ ) ( ″ ).

Hatch marks can probably be traced to hatching in art works, where the pattern of the hatch marks represents a unique tone or hue. Different patterns indicate different tones.

Ice hockey rink

An ice hockey rink is an ice rink that is specifically designed for ice hockey, a team competing sport. Alternatively it is used for other sports such as broomball, ringette and rink bandy. It is a rectangle with rounded edges and surrounded by a wall approximately 1 metre (39 in) high called the boards.

Key (basketball)

The key, officially referred to as the free throw lane by the National Basketball Association (NBA), the National Collegiate Athletic Association (NCAA), and the National Association of Intercollegiate Athletics (NAIA), the restricted area by the international governing body FIBA, and colloquially as the lane or the paint, is a marked area on a basketball court surrounding the basket. It is bounded by the endline, the free-throw line and two side lines (freebody lines), and usually painted in a distinctive color. It is a crucial area on the court where much of the game's action takes place.

Dimensions of the key area have varied through the history of the game. Since the 2010 FIBA rule amendments (implemented following the 2010 FIBA World Championship), its shape is rectangular for games sanctioned by all three associations, 16 feet (4.9 m) wide for both NBA and FIBA keys, and 12 feet (3.7 m) for NCAA and NAIA keys. Prior to 2006, the key in FIBA-sanctioned tournaments was a trapezoidal shape.

The most-commonly enforced rule on the key is the "three seconds rule" in which the team of a player on offense who stays on the key for more than three seconds loses possession of the ball. Another rule is the lane violation which occurs if a player from either team enters the key before a free-throw shooter releases the ball in the act of shooting. A recent innovation is the introduction of the restricted area arc directly underneath the basket where the defending player cannot force an offensive foul on the opposing player.

Muffed punt

In gridiron football, a muffed punt is defined as "touching of the ball prior to possessing the ball.”

A muffed punt occurs when there is an "uncontrolled touch" of the football by a player on the returning team after it is punted. This can occur when:

The kicking team interferes with the other team's right to catch the punt

A player on the kicking team is struck unaware by the football running down-field to cover the punt.

A player attempts to return the ball, makes contact with it but cannot retain the ball in his hands and it comes loose.

To be a fumble, the receiving team must possess the football, then lose control. In the case of a fumble, the ball is live and can be returned by the team that recovers the ball. In the case of a muffed punt, it is possible for the punting team to recover the ball and continue the drive, but at least in NCAA and NFL rules, they cannot advance the ball on that same play. Rules vary by league about how to handle a muffed punt.

Nonetheless, a muffed punt is a turnover. In the NFL, a muffed punt recovered by the kicking team cannot be challenged by a coach for review because all turnovers are automatically reviewed.

Skeletal formula

The skeletal formula, also called line-angle formula or shorthand formula, of an organic compound is a type of molecular structural formula that serves as a shorthand representation of a molecule's bonding and some details of its molecular geometry. A skeletal formula shows the skeletal structure or skeleton of a molecule, which is composed of the skeletal atoms that make up the molecule. It is represented in two dimensions, as on a piece of paper. It employs certain conventions to represent carbon and hydrogen atoms, which are the most common in organic chemistry.

An early form of this representation was first developed by the organic chemist Friedrich August Kekulé von Stradonitz, while the modern form is closely related to and influenced by the Lewis (dot) structure of molecules and their valence electrons. For this reason, they are sometimes termed Kekulé structures or Lewis-Kekulé structures. Skeletal formulae have become ubiquitous in organic chemistry, partly because they are relatively quick and simple to draw, and also because the curved arrow notation used for discussions of reaction mechanism and/or delocalization can be readily superimposed. As in Lewis structures, covalent bonds are indicated by line segments, with a doubled or tripled line segment indicating double or triple bonding, respectively. Likewise, skeletal formulae indicate formal charges associated with each atom (although lone pairs are usually optional, see below). In fact, skeletal formulae can be thought of as abbreviated Lewis structures that observe the following simplifications: (1) Carbon atoms are represented by the vertices (intersections or termini) of line segments. For clarity, methyl groups are often explicitly written out as Me or CH3, while (hetero)cumulene carbons are frequently represented by a heavy center dot.

(2) Hydrogen atoms attached to carbon are implied. An unlabeled vertex is understood to represent a carbon attached to the number of hydrogens required to satisfy the octet rule, while a vertex labeled with a formal charge and/or nonbonding electron(s) is understood to have the number of hydrogen atoms required to give the carbon atom these indicated properties. Optionally, acetylenic and formyl hydrogens can be shown explicitly for the sake of clarity.

(3) Hydrogen atoms attached to a heteroatom are shown explicitly. The heteroatom and hydrogen atoms attached thereto are usually shown as a single group (e.g., OH, NH2) without explicitly showing the hydrogen–heteroatom bond. Heteroatoms with simple alkyl or aryl substituents, like methoxy (OMe) or dimethylamino (NMe2), are sometimes shown in the same way, by analogy.

(4) Lone pairs on carbene carbons must be indicated explicitly while lone pairs in other cases are optional and are shown only for emphasis. In contrast, formal charges and unpaired electrons on main-group elements are always explicitly shown.In the standard depiction of a molecule, the canonical form (resonance structure) with the greatest contribution is drawn. However, the skeletal formula is understood to represent the "real molecule" — that is, the weighted average of all contributing canonical forms. Thus, in cases where two or more canonical forms contribute with equal weight (e.g., in benzene, or a carboxylate anion) and one of the canonical forms is selected arbitrarily, the skeletal formula is understood to depict the true structure, containing equivalent bonds of fractional order, even though the delocalized bonds are depicted as nonequivalent single and double bonds.

Several other methods for depicting chemical structures are also commonly used in organic chemistry (though less frequently than skeletal formulae). For example, conformational structures look similar to skeletal formulae and are used to depict the approximate positions of the atoms of a molecule in three-dimensional space, as a perspective drawing. Other types of representations, e.g., Newman projections, Haworth projections and Fischer projections, also look somewhat similar to skeletal formulae. However, there are slight differences in the conventions used, and the reader needs to be aware of them in order to understand the structural details that are encoded in these depictions. While skeletal and conformational structures are also used in organometallic and inorganic chemistry, the conventions employed also differ somewhat.

Slot (ice hockey)

In hockey, the slot is the area on the hockey rink directly ahead of the goaltender between the faceoff circles on each side. It is sometimes referred to as the "scoring area".

The "deep" or "high" slot refers to the area from the top of the circles, farthest from the goaltender, to the end of the slot at the hash marks. The distinction of where the deep slot begins is contentious. In general, it is the defenceman's responsibility to guard offensive players in the slot, while the offside winger covers offensive players in the deep slot. Because the deep slot is protected by an offensively minded winger and not a defenceman, forwards will often hover in the deep slot waiting for an opportunity to move towards the net for a scoring opportunity.

Tally marks

Tally marks, also called hash marks, are a unary numeral system. They are a form of numeral used for counting. They are most useful in counting or tallying ongoing results, such as the score in a game or sport, as no intermediate results need to be erased or discarded.

However, because of the length of large numbers, tallies are not commonly used for static text. Notched sticks, known as tally sticks, were also historically used for this purpose.

Turn and slip indicator

In aviation, the turn and slip indicator (T/S, a.k.a. turn and bank indicator) and the turn coordinator (TC) variant are essentially two aircraft flight instruments in one device. One indicates the rate of turn, or the rate of change in the aircraft's heading; the other part indicates whether the aircraft is in coordinated flight, showing the slip or skid of the turn. The slip indicator is actually an inclinometer that at rest displays the angle of the aircraft's transverse axis with respect to horizontal, and in motion displays this angle as modified by the acceleration of the aircraft.

Yard lines

Yard lines are a place on an American football field marking the distance from the line of scrimmage to the closest goal line.White markings on the field identify the distance from the end zone. Inbound lines, or hash marks, are short parallel lines that mark off 1 yard (0.91 m) increments. Usually, every 5 yards (4.6 m) they run the width of the field. A one yard wide is placed at each end of the field; this line is marked at the center of the two-yard line in professional play and at the three-yard line in college play. Numerals that display the distance from the closest goal line in multiples of ten are placed on both sides of the field every ten yards. Lines marked along the ends and sides of the field are known respectively as the end lines and sidelines, and goal lines.

Levels of play
Play clock

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