n. [ AS. gnæt. ] 1. (Zool.) A blood-sucking dipterous fly, of the genus Culex, undergoing a metamorphosis in water. The females have a proboscis armed with needlelike organs for penetrating the skin of animals. These are wanting in the males. In America they are generally called mosquitoes. See Mosquito. [ 1913 Webster ]

2. Any fly resembling a Culex in form or habits; esp., in America, a small biting fly of the genus Simulium and allies, as the buffalo gnat, the black fly, etc. [ 1913 Webster ]

Gnat catcher (Zool.), one of several species of small American singing birds, of the genus Polioptila, allied to the kinglets. --
Gnat flower, the bee flower. --
Gnat hawk (Zool.), the European goatsucker; -- called also gnat owl. --
Gnat snapper (Zool.), a bird that catches gnats. --
Gnat strainer, a person ostentatiously punctilious about trifles. Cf. Matt. xxiii. 24. [ 1913 Webster ]

a. [ Gr. gna`qos the jaw. ] (Anat.) Of or pertaining to the jaw. [ 1913 Webster ]

Gnathic index, in a skull, the ratio of the distance from the middle of the nasofrontal suture to the basion (taken equal to 100), to the distance from the basion to the middle of the front edge of the upper jaw; -- called also alveolar index. [ 1913 Webster ]

Skulls with the gnathic index below 98 are orthognathous, from 98 to 103 mesognathous, and above 103 are prognathous. Flower. [ 1913 Webster ]

‖n.; pl. Gnathidia [ NL., fr. Gr. gna`qos the jaw. ] (Zool.) The ramus of the lower jaw of a bird as far as it is naked; -- commonly used in the plural. [ 1913 Webster ]

n. [ Gr. gna`qos the jaw. ] (Zool.) Any one of the mouth appendages of the Arthropoda. They are known as mandibles, maxillæ, and maxillipeds.

{ } a. [ L. Gnatho, name of a parasite in the “Eunuchus” of Terence, Gr. &unr_;; hence, a parasite in general. ] Flattering; deceitful. [ Obs. ] [ 1913 Webster ]

n. [ Gr. gna`qos the jaw + -pod. ] (Zool.) A gnathopodite or maxilliped. See Maxilliped. [ 1913 Webster ]

n. (Zool, ) Any leglike appendage of a crustacean, when modified wholly, or in part, to serve as a jaw, esp. one of the maxillipeds. [ 1913 Webster ]

n. [ Gr. gna`qos the jaw + &unr_; a roof. ] (Zool.) One of a pair of broad plates, developed from the outer maxillipeds of crabs, and forming a cover for the other mouth organs. [ 1913 Webster ]

‖n. pl. [ NL., from Gr. gna`qos the jaw + &unr_;, &unr_;, the mouth. ] (Zool.) A comprehensive division of vertebrates, including all that have distinct jaws, in contrast with the leptocardians and marsipobranchs (Cyclostoma), which lack them. [ Written also Gnathostomata. ] [ 1913 Webster ]

‖n.; pl. Gnathothecae [ NL., fr. Gr. gna`qos the jaw + &unr_; a box. ] (Zool.) The horney covering of the lower mandible of a bird. [ 1913 Webster ]