- first base - the base that must be touched first by a base runner in baseball
--1 is a kind of base, bag
- first base, first - the fielding position of the player on a baseball team who is stationed at first base
--2 is a kind of position
--2 is a member of baseball team- first base - the initial stage in accomplishing something; "we didn't get to first base with that approach"
--3 is a kind of first step, initiative, opening move, opening
- first base, first - the fielding position of the player on a baseball team who is stationed at first base