The six-hour clock (Italian: sistema orario a 6 ore), also called the Roman (alla romana) or the Italian (all'italiana) system, is a timekeeping system used in Italy. In this system, the day starts at the evening Ave Maria at the end of twilight, approximately half an hour after sunset, and the following 24 hours are divided into four cycles of six hours each.
The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods: a.m. (from Latin ante meridiem, translates to, before midday) and p.m. (from Latin post meridiem translates to, past midday). Each period consists of 12 hours numbered: 12 (acting as zero), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11. The 24 hour/day cycle starts at 12 midnight (may be indicated as 12 a.m.), runs through 12 noon (may be indicated as 12 p.m.), and continues to the midnight at the end of the day. The 12-hour clock has been developed from the middle of the second millennium BC to the 16th century AD.
The 12-hour time convention is common in several English-speaking nations and former British colonies, as well as a few other countries.24-hour clock
The 24-hour clock is the convention of time keeping in which the day runs from midnight to midnight and is divided into 24 hours, indicated by the hours passed since midnight, from 0 to 23. This system is the most commonly used time notation in the world today, and is used by international standard ISO 8601.A limited number of countries, particularly English-speaking, use the 12-hour clock, or a mixture of the 24- and 12-hour time systems. In countries where the 12-hour clock is still dominant, some professions prefer to use the 24-hour clock. For example, in the practice of medicine the 24-hour clock is generally used in documentation of care as it prevents any ambiguity as to when events occurred in a patient's medical history. In the United States and a handful of other countries, it is popularly referred to as military time.Six-hour clock
Six-hour clock may refer to:
Thai six-hour clock
Italian six-hour clockThai six-hour clock
The six-hour clock is a traditional timekeeping system used in the Thai and formerly the Lao language and the Khmer language, alongside the official 24-hour clock. Like other common systems, it counts twenty-four hours in a day, but divides the day into four quarters, counting six hours in each. The hours in each quarter (with the exception of the sixth hour in each quarter) are told with period-designating words or phrases, which are:
... mong chao (Thai: ...โมงเช้า, [mōːŋ tɕʰáːw]) for the first half of daytime (07:00 to 12:59)
Bai ... mong (บ่าย...โมง, [bàːj mōːŋ]) for the latter half of daytime (13:00 to 18:59)
... thum (...ทุ่ม, [tʰûm]) for the first half of nighttime (19:00 to 00:59)
Ti ... (ตี..., [tīː]) for the latter half of nighttime (01:00 to 06:59)These terms are thought to have originated from the sounds of traditional timekeeping devices. The gong was used to announce the hours in daytime, and the drum at night. Hence the terms mong, an onomatopoeia of the sound of the gong, and thum, that of the sound of the drum. Ti is a verb meaning to hit or strike, and is presumed to have originated from the act of striking the timekeeping device itself. Chao and bai translate as morning and afternoon respectively, and help to differentiate the two daytime quarters.
The sixth hours of each quarter are told by a different set of terms. The sixth hour at dawn is called yam rung (ย่ำรุ่ง, [jâm rûŋ]), and the sixth hour at dusk is called yam kham (ย่ำค่ำ, [jâm kʰâm]), both references to the act of striking the gong or drum in succession to announce the turning of day (yam), where rung and kham, meaning dawn and dusk, denote the time of these occurrences. The midday and midnight hours are respectively known as thiang (เที่ยง, [tʰîaːŋ], or thiang wan, เที่ยงวัน, [tʰîaːŋ wān]) and thiang khuen (เที่ยงคืน, [tʰîaːŋ kʰɯ̄ːn]), both of which literally translate as midday and midnight.Midnight is also called song yam (สองยาม, [sɔ̌ːŋ jāːm]; note that yam is a different word), a reference to the end of the second three-hour period of the night watch (song translates as the number two). In addition, hok (6) thum and ti hok may also be used to refer to the hours of midnight and dawn, following general usage for the other hours, although more rarely; and the fourth to sixth hours of the second daytime half may also be told as ...mong yen (...โมงเย็น, [mōːŋ jēn]), yen meaning evening.
The system has been used in some form since the days of the Ayutthaya Kingdom, but was codified similarly to its present form only in 1901 by King Chulalongkorn in Royal Gazette 17:206. Nowadays, it is used only in colloquial speech. However, a corrupted form of the six-hour clock is more frequently encountered, where usually the first half of daytime (including the sixth hour of the preceding quarter) is counted as in the twelve-hour clock, i.e. hok (6) mong chao, chet (7) mong, etc., up to sip et (11) mong.
The six-hour clock system was abolished in Laos and Cambodia during the French protectorate, and the French 24-hour clock system (for example, 3h00) has been used since.
A comparison of the systems is as follows:
* The word chao (เช้า) is optional here since the numbers 7 to 11 are not used elsewhere
** Conversationally, si mong yen (สี่โมงเย็น) and ha mong yen (ห้าโมงเย็น) are also spoken if considered as evening
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