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biped vs. quadruped

biped

[bahy-ped] / ˈbaɪ pɛd /

noun

a two-footed animal.

adjective

having two feet.

quadruped

[kwod-roo-ped] / ˈkwɒd rʊˌpɛd /

adjective

four-footed.

noun

an animal, especially a mammal, having four feet.