[fəːst], (Numeral)

- coming before all others in time or order; earliest; 1st
(e.g: his first wife)

- foremost in position, rank, or importance
(e.g: the doctor's first duty is to respect this right)

- with a specified part or person in a leading position
(e.g: the car plunged nose first into the river)

- at first
- first and foremost
- first and last
- first come, first served
- first of all
- first off
- first past the post
- first thing
- first things first
- first up
- from first to last
- from the first
- in the first place
- of the first order

Old English fyr(e)st; of Germanic origin, related to Old Norse fyrstr and German Fürst ‘prince’, from an Indo-European root shared by Sanskrit prathama, Latin primus, and Greek prōtos

definition by Oxford Dictionaries