What does biped mean?
A biped is any animal that habitually stands or moves about on two legs rather than four. The word applies most naturally to human beings — we are, anatomically speaking, the most committed bipeds in the animal kingdom — but it also describes birds, which walk on two legs by default, and extinct relatives of humans whose fossilized skeletons reveal the shift from tree-dwelling to upright walking. In scientific contexts the term appears constantly: researchers classify species as obligate bipeds, meaning they must walk on two legs, or facultative bipeds, meaning they can switch between two and four legs as circumstances demand. Related forms include the adjective "bipedal" and the noun "bipedalism," which names the mode of locomotion itself. Though technical in flavor, "biped" occasionally surfaces in casual speech as a wry way of referring to people, lending it a slightly detached or humorous tone when used outside academic settings. Its counterpart is "quadruped," an animal that gets around on four legs.
nounA biped is an animal that uses two legs for walking or standing, especially a human being.
- An animal that moves on two legs (especially humans).
"Humans are the only bipeds capable of running a marathon in under two hours."
"The fossil record suggests that early hominins became bipeds long before their brains enlarged."
"Unlike most birds, the ostrich is a flightless biped that relies on its powerful legs to escape predators."
Standard plural; used both for individual animals and for categories of species.
"Early bipeds left distinctive footprint trails preserved in volcanic ash."
Every step you take is a controlled fall — something no other animal does quite like a biped.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of biped
Biped comes from the Latin "bipēs" (stem "biped-"), formed from "bi-," meaning "two," plus "pēs," meaning "foot." English adopted the word around the early seventeenth century, alongside related terms such as "bipedal." The same Latin root "pēs" gave English a wide family of foot-related words, including "pedal," "pedestrian," and "impede."
Related word forms
How biped is actually used
"Biped" is a technical term common in zoology, paleoanthropology, and anatomy; it can sound clinical or humorous when applied casually to people. The adjective form "bipedal" is more frequent in scientific writing.
Easily confused with biped
A quadruped walks on four legs, while a biped walks on two.