bipedal
bipedal — adjective
1. describes the way a creature moves when it uses its two back legs for standing a
describes the way a creature moves when it uses its two back legs for standing and walking, keeping the front part of its body off the ground.
Humans are bipedal, which frees their hands for using tools.
bipedal + frees hands (advantage of trait)
The fossil showed that early humans had already developed a bipedal walking style.
Ostriches are bipedal birds that can run faster than most four-legged animals.
Dr. Okafor studied how bipedal movement changes the shape of human bones over time.
Mei-Lin designed a small bipedal robot that could walk across uneven ground.
- two-legged
everyday equivalent; also describes furniture (two-legged stool), which bipedal cannot
- upright
broader meaning emphasising vertical posture rather than number of legs
- quadrupedal
walking on four legs, the opposite form of locomotion
- four-legged
everyday antonym; describes animals that use all four limbs for walking
用法筆記
The standard term in scientific and academic writing; in everyday conversation, two-legged is more common for describing animals.
常見錯誤
bipedal — noun
1. a creature whose natural way of moving is to stand and walk on two legs, keeping
a creature whose natural way of moving is to stand and walk on two legs, keeping the front part of its body off the ground.
As a biped, the kangaroo uses its strong tail to keep balance while hopping.
biped as standard noun form
Humans are not the only bipeds — birds also walk upright on two legs.
bipeds as plural count noun
The park ranger explained that penguins are bipeds adapted to life in cold ocean waters.
In biology class, the students learned that ostriches are the fastest bipeds on land.
The fossil skeleton belongs to an early biped that lived more than three million years ago.
- biped
identical meaning; biped is the standard noun, while bipedal is the adjective form
- quadruped
a four-legged animal
用法筆記
The standard noun in both scientific and general contexts is biped (without the -al ending). Bipedal is almost exclusively an adjective; using it as a noun (e.g., "a bipedal", "bipedals") is rare and may sound unnatural to native speakers.