WordNet (r) 3.0 (2006):
third base n 1: the base that must be touched third by a base runner in baseball; "he was cut down on a close play at third" [syn: third base, third] 2: the fielding position of the player on a baseball team who is stationed near the third of the bases in the infield (counting counterclockwise from home plate); "he is playing third" [syn: third base, third]