NOUN (2)

1. any of various small biting flies: midges; biting midges; black flies; sand flies;

2. (British usage) mosquito;

The Collaborative International Dictionary of English v.0.48:

Gnat \Gnat\, n. [AS. gn[ae]t.]
   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]

WordNet (r) 3.0 (2006):

gnat
    n 1: any of various small biting flies: midges; biting midges;
         black flies; sand flies
    2: (British usage) mosquito

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "gnat":
   crumb, dot, drop, droplet, fleck, flyspeck, grain, iota, jot,
   microbe, microorganism, midge, minim, minutia, minutiae, mite,
   mote, particle, pinhead, pinpoint, point, scrap, snip, snippet,
   speck, tittle, vanishing point



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

GNAT
       GNU Ada Translator (GNU)


The Free On-line Dictionary of Computing (30 December 2018):

Gnat

    An Ada compiler written in Ada using
   the gcc code generator to allow easy porting to a
   variety of platforms.  Gnat is the only Ada compiler that
   completely implements the Ada standard, including all the
   annexes.

   The compiler is released under the GNU license and is
   currently maintained by Ada Core Technologies (ACT).

   (http://gnat.com/).

   (1999-06-24)


Easton's 1897 Bible Dictionary:

Gnat
   only in Matt. 23:24, a small two-winged stinging fly of the
   genus Culex, which includes mosquitoes. Our Lord alludes here to
   the gnat in a proverbial expression probably in common use, "who
   strain out the gnat;" the words in the Authorized Version,
   "strain at a gnat," being a mere typographical error, which has
   been corrected in the Revised Version. The custom of filtering
   wine for this purpose was common among the Jews. It was founded
   on Lev. 11:23. It is supposed that the "lice," Ex. 8:16 (marg.
   R.V., "sand-flies"), were a species of gnat.