first (adj., adv.)

Old English fyrst "foremost, going before all others; chief, principal," also (though rarely) as an adverb, "at first, originally," superlative of fore; from Proto-Germanic *furista- "foremost" (source also of Old Saxon fuirst "first," Old High German furist, Old Norse fyrstr, Danish første, Old Frisian ferist, Middle Dutch vorste "prince," Dutch vorst "first," German Fürst "prince"), from PIE *pre-isto-, superlative of *pre-, from root *per- (1) "forward," hence "in front of, before, first, chief."

The usual Old English superlative word was not fyrst, but forma, which shows more clearly the connection to fore. Forma became Middle English firme "first, earliest," but this has not survived.

First aid is that given at the scene, pending the arrival of a doctor. First lady as an informal title for the wife of a U.S. president was in use by 1908, short for First lady of the land (by 1863 with reference to the president's wife); the earlier title was simply Lady (1841). First name is attested from mid-13c. First base "a start" in any sense (1938) is a figurative use from baseball.

First fruits is from late 14c. as "earliest productions of the soil;" 1590s as "first results" of any activity or endeavor. First love is from 1741 as "one's first experience of romantic love;" 1971 as "one's favorite occupation or pastime." First floor is from 1660s as "story built on or just above the ground" (now U.S.); 1865 as "story built next above the ground."

first (n.)

1560s, "that which is first," from first (adj.). Meaning "first day of the month" is by 1590s. In music, "instrument or voice that takes the highest or chief part of its class," 1774. From 1909 as the name of the lowest gear in an engine. In British schools colloquial use, "highest rank in an examination," 1850.

Definitions of first
first (n.)
the first or highest in an ordering or series;
He wanted to be the first
Synonyms: number one
first (n.)
the first element in a countable series;
the first of the month
Synonyms: number one / number "
first (n.)
the time at which something is supposed to begin;
Synonyms: beginning / commencement / outset / get-go / start / kickoff / starting time / showtime / offset
first (n.)
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);
Synonyms: first base
first (n.)
an honours degree of the highest class;
Synonyms: first-class honours degree
first (n.)
the lowest forward gear ratio in the gear box of a motor vehicle; used to start a car moving;
Synonyms: first gear / low gear / low
first (adj.)
serving to begin;
the first verse
Synonyms: beginning
first (adj.)
preceding all others in time or space or degree;
the first day of spring
the first meetings of the new party
the first time
the first house on the right
his first political race
her first baby
the first phase of his training
first (adj.)
indicating the beginning unit in a series;
Synonyms: st
first (adj.)
serving to set in motion;
his first (or maiden) speech in Congress
first (adj.)
ranking above all others;
was first in her class
Synonyms: foremost / world-class
first (adj.)
highest in pitch or chief among parts or voices or instruments or orchestra sections;
played first horn
the first violin section
first soprano
first (adv.)
before anything else;
first we must consider the garter snake
Synonyms: firstly / foremost / first of all / first off
first (adv.)
the initial time;
when Felix first saw a garter snake
first (adv.)
before another in time, space, or importance;
I was here first
let's do this job first
first (adv.)
prominently forward;
Synonyms: foremost