A leg was a part of a body or furniture.
Cricket pads were worn on the legs whilst playing the game. Nyssa once mistakenly called them "strange leggings" and claimed that she couldn't get used to seeing the Doctor wearing them. (AUDIO: Autumn)
Mrs Harcourt lost her leg to the London Blitz. Nanogenes reprogrammed with human genes cured her injuries and grew her leg back. She asked Doctor Constantine what had happened, and he suggested she had miscounted her legs. (TV: The Doctor Dances)
Amy Pond was once introduced by the Eleventh Doctor as "the Legs". (TV: The Impossible Astronaut) Clara Oswald once said that Amy is made of legs, when shown an image of her via the TARDIS’s records. (HOMEVID: Clara and the TARDIS)