In biology, a nymph is the immature form of some invertebrates, particularly insects, which undergoes gradual metamorphosis (hemimetabolism) before reaching its adult stage. Unlike a typical larva, a nymph's overall form already resembles that of the adult, except for a lack of wings (in winged species). In addition, while a nymph moults it never enters a pupal stage. Instead, the final moult results in an adult insect. Nymphs undergo multiple stages of development called instars.
This is the case, for example, in Orthoptera (crickets and grasshoppers), Hemiptera (cicadas, shield bugs, etc.), mayflies, termites, cockroaches, mantises, stoneflies and Odonata (dragonflies and damselflies).
Nymphs of aquatic insects, as in the Odonata, Ephemeroptera, and Plecoptera, are also called naiads, an Ancient Greek name for mythological water nymphs. In older literature, these were sometimes referred to as the heterometabolous insects, as their adult and immature stages live in different environments (terrestrial vs. aquatic).
In fly fishing with artificial flies, this stage of aquatic insects is the basis for an entire series of representative patterns for trout. They account for over half of the over all patterns regularly fished in the United States.
In Greek mythology, a nymph (Ancient Greek: νύμφη) is a female nature-spirit.
Nymph may also mean:
Nymph (biology), the immature form of an insect having incomplete metamorphosis
Nymph (fishing), a lure that imitates the insect life-stage
HMS Nymph, a Royal Navy sloop launched in 1778
USS Nymph (1863), a Union Navy steamer in the American Civil War
BN-3 Nymph, original name of the NAC Freelance airplane
The Nymphs (poem), by Leigh Hunt, published in 1818
Nymph (Central Figure for "The Three Graces"), a bronze sculpture in Washington, D.C.
The Nymphs, a 1990s US-American alternative rock band
The Nymphs (album), released in 1991
The Nymph (Ninfa plebea), a 1996 Italian film directed by Lina Wertmüller
Nymph (1973 film), a 1973 American film
Nymph (2009 film), a 2009 Thai film
Nymphs (Finnish TV series), a 2013 Finnish TV series
Nymph, the "Beta Angeloid: Electronic Warfare Type" in the anime Sora no Otoshimono
Nymph (Dungeons & Dragons), a monster in the Dungeons & Dragons role-playing game
Nymph, Alabama, a populated place in Conecuh County, Alabama