- the base to the left of the pitcher, the first of the four bases that a base runner attempts to reach safely
- the defensive position played by the first baseman
See first base in American Heritage Dictionary 4
a. The first of the bases in the infield, counterclockwise from home plate.
b. The fielding position occupied by the first baseman.
- Slang The first stage or step toward completion or success: “He never got to first base with any of his big wheels and deals” (Ross Macdonald).
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