I am a homonym that can be spelled two ways and have more than one meaning. Spelled one way, I am a part of your body. Humans have two. Horses (and many other animals) have four. People often wear socks on this part of their body, but horses don't put socks on! However, some horses are born with sock-like markings. Joey, the brave and intelligent horse in the movie War Horse, had these white .....