Bipedalism

Bipedalism is standing, or moving for example by walking, running, or hopping, on two appendages (typically legs). An animal or machine that usually moves in a bipedal manner is known as a biped (//), meaning "two feet" (Latin bi = two + ped = foot).
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Noun
1. the bodily attribute of being bipedal; having two feet; "bipedalism made the human form of birth possible"
(hypernym) bodily property