Source : Webster's Revised Unabridged Dictionary (1913)

Bedbug \Bed"bug`\, n. (Zo["o]l.)
   A wingless, bloodsucking, hemipterous insect ({Cimex
   Lectularius}), sometimes infesting houses and especially
   beds. See Illustration in Appendix.

Source : WordNet®

bedbug
     n : bug of temperate regions that infests especially beds and
         feeds on human blood [syn: {bed bug}, {chinch}, {Cimex
         lectularius}]