Source : Webster's Revised Unabridged Dictionary (1913)

Swiftlet \Swift"let\, n. (Zo["o]l.)
   Any one of numerous species of small East Indian and Asiatic
   swifts of the genus {Collocalia}. Some of the species are
   noted for furnishing the edible bird's nest. See Illust.
   under {Edible}.

Source : WordNet®

swiftlet
     n : swift of eastern Asia; produces the edible bird's nest [syn:
          {Collocalia inexpectata}]