serving to begin

serving to set in motion

ranking above all others

highest in pitch or chief among parts or voices or instruments or orchestra sections

the initial time

before another in time, space, or importance

prominently forward

the first element in a countable series

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)

the time at which something is supposed to begin

the lowest forward gear ratio in the gear box of a motor vehicle; used to start a car moving