The Collaborative International Dictionary of English v.0.48:

Biped \Bi"ped\, n. [L. bipes; bis twice + pes, pedis, ?oot: cf.
   F. bip[`e]de.]
   A two-footed animal, as man.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Biped \Bi"ped\, a.
   Having two feet; two-footed.
   [1913 Webster]

         By which the man, when heavenly life was ceased,
         Became a helpless, naked, biped beast.   --Byrom.
   [1913 Webster]

WordNet (r) 3.0 (2006):

biped
    adj 1: having two feet [syn: bipedal, biped, two-footed]
           [ant: four-footed, quadruped, quadrupedal]
    n 1: an animal with two feet

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "biped":
   amphibian, aquatic, biaxial, bicameral, bicuspid, bifid, biform,
   binocular, binomial, binominal, bipartite, bipetalous, bipinnate,
   bisexual, bivalent, canine, cannibal, carnivore, cosmopolite,
   feline, gnawer, herbivore, insectivore, invertebrate, mammal,
   mammalian, marsupial, marsupialian, omnivore, primate, quadruped,
   reptile, rodent, ruminant, scavenger, ungulate, unibivalent,
   varmint, vermin, vertebrate