first

first - noun

the first or highest in an ordering or series

the first element in a countable series

the time at which something is supposed to begin

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)

an honours degree of the highest class

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

first - adjective

preceding all others in time or space or degree
indicating the beginning unit in a series
serving to set in motion
serving to begin
ranking above all others
highest in pitch or chief among parts or voices or instruments or orchestra sections

first - adverb