leg
A limb used for standing and walking, or a support.
A leg is one of the limbs you use to stand and walk. Humans have two legs, while insects have six and spiders have eight. Your leg extends from your hip down to your foot, containing strong bones and muscles that let you run, jump, kick, and balance.
Animals that walk on legs are called terrestrial (land-dwelling) creatures, and having legs was a major evolutionary development that allowed animals to move efficiently on land. Different animals evolved different numbers and types of legs depending on their needs: a cheetah's long, powerful legs help it sprint at incredible speeds, while a grasshopper's bent legs act like springs for jumping.
The word also describes parts of other objects that support them from below. Tables and chairs have legs that hold them up off the ground. A tripod (a three-legged stand for a camera) gets its name from having three legs.
In travel, a leg means one part of a longer journey. If you fly from New York to Los Angeles with a stop in Chicago, each flight is a leg of your trip. Similarly, in a relay race, each runner completes one leg of the race before passing the baton.
You might hear phrases like “pulling someone's leg” (teasing them) or not having “a leg to stand on” (having no good argument or excuse), where leg takes on figurative meanings beyond the physical limb.