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

first - adverb

• before anything else
• the initial time
• before another in time, space, or importance
• prominently forward

first - thesaurus

1st   beginning   commencement   firstly   foremost   inaugural   initiative   initiatory   kickoff   low   maiden   offset   outset   showtime   start