from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A small round bag filled with plastic pellets or other material and used in games that require its being kept aloft with the feet.
- n. Any of the games in which such a bag is used.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A small beanbag or sandbag used as a ball in a number of sports and games. It is typically controlled by the feet, but in some sports every part of the body except the hands and arms may be used.
- n. A generic name for the sports which use the footbag.
foot + bag, by analogy with football. (Wiktionary)