Source : Webster's Revised Unabridged Dictionary (1913)

Branchia \Bran"chi*a\, n.; pl. {Branchi[ae]}. [L., fr. Gr. ?,
   pl. of ?.] (Anat.)
   A gill; a respiratory organ for breathing the air contained
   in water, such as many aquatic and semiaquatic animals have.

Source : WordNet®

branchiae
     See {branchia}

branchia
     n : respiratory organ of aquatic animals that breathe oxygen
         dissolved in water [syn: {gill}]
     [also: {branchiae} (pl)]