first base, first -- (the fielding position of the player on a baseball team who is stationed at first of the bases in the infield (counting counterclockwise from home plate))
first gear, first, low gear, low -- (the lowest forward gear ratio in the gear box of a motor vehicle; used to start a car moving)
Overview of adj first
The adj first has 6 senses
first -- (preceding all others in time or space or degree; "the first house on the right"; "the first day of spring"; "his first political race"; "her first baby"; "the first time"; "the first meetings of the new party"; "the first phase of his training")
first, 1st -- (indicating the beginning unit in a series)
inaugural, initiative, initiatory, first, maiden -- (serving to set in motion; "the magazine's inaugural issue"; "the initiative phase in the negotiations"; "an initiatory step toward a treaty"; "his first (or maiden) speech in Congress"; "the liner's maiden voyage")
beginning, first -- (serving to begin; "the beginning canto of the poem"; "the first verse")
first, foremost, world-class -- (ranking above all others; "was first in her class"; "the foremost figure among marine artists"; "the top graduate")
first -- (highest in pitch or chief among parts or voices or instruments or orchestra sections; "first soprano"; "the first violin section"; "played first horn")