weight bearing and locomotive anatomical structure, usually having a columnar shape, function as "extensible struts"

A leg is something used to support things; to hold them up. Birds and humans have two legs. Some objects, for example tables and chairs, also have legs to hold them up.

The human leg
Legs, sitting sieza.

Animals normally have 2 or 4 legs (vertebrates, which are animals with a backbone), or 6, 8, or 12 (arthropods, for example insects and spiders). Centipedes and millipedes have a lot more legs, but not exactly a hundred or a thousand as their names make people who do not know them think. Humans have 2 legs, complete with feet.

Biped is an animal with two legs and quadruped is an animal with four legs.

People also use the word "leg" in idioms, for example:

  • you do not have a leg to stand on (that means "you have no support; you have no chance in this discussion")
  • to leg it (to run)
  • to pull someone's leg (to play a little joke on someone for fun by trying to make them believe something that is not true)