Informal.
1. the numeral zero, often used to indicate the failure of a team to score in a game or unit of a game: a pitchers' duel, with nothing but goose eggs on the scoreboard.
2. a lump raised by a blow, esp. on the head.
[ 1350-1400; 1885-90, Amer., for def. 1; ME: the egg of a goose ]