first meaning
EN
[fɜːst] [fɝst] [-ɜː(r)st] 
US WFirst
- First or 1st is the ordinal form of the number one (#1).
- First or 1st may also refer to:
- First (Grindelwald), minor summit below the Schwarzhorn in the Bernese Alps in Switzerland
- First (Kandersteg), mountain in Bernese Alps in Switzerland
- First (magazine), a Singaporean movie magazine
- First grade, in primary education
- For Inspiration and Recognition of Science and Technology (FIRST), a world-wide youth robotics competition
- First, a British undergraduate degree classification
- FirstGroup, a large British transportation company operating buses, trains, coaches and trams
EN First 
- NounPLfirstsSUF-est
- (uncountable) The person or thing in the first position.
- He was the first to complete the course.
- (uncountable) The first gear of an engine.
- (countable) Something that has never happened before; a new occurrence.
- This is a first. For once he has nothing to say.
- (countable, baseball) first base.
- There was a close play at first.
- (countable, Britain, colloquial) A first-class honours degree.
- (countable, colloquial) A first-edition copy of some publication.
- A fraction of an integer ending in one.
- one forty-first of the estate
- (obsolete) Time; time granted; respite.
- (uncountable) The person or thing in the first position.
- Adjective
- Preceding all others of a series or kind; the ordinal of one; earliest.
- Sunning himself on the board steps, I saw for the first time Mr. Farquhar Fenelon Cooke. He was dressed out in broad gaiters and bright tweeds, like an English tourist, and his face might have belonged to Dagon, idol of the Philistines.
- Most eminent or exalted; most excellent; chief; highest.
- Preceding all others of a series or kind; the ordinal of one; earliest.
- Adverb
- Before anything else; firstly.
- Clean the sink first, before you even think of starting to cook.
- Before anything else; firstly.
- More Examples
- Used in the Middle of Sentence
- Margaret Thatcher was the first ever female Prime Minister and was a Conservative party candidate for that office.
- The Baggies had offered little threat until the 28th minute, but when their first chance came it was a clear one.
- I will read most of the book, but skip the first chapter because the video covered it.
- Used in the Beginning of Sentence
- First identified in 2007 from a child with febrile illness, SAFV are found in the stool of children with nonpolio acute flaccid paralysis and healthy children in Pakistan.
- First we'll tenon this part, then we'll make a mortise that will fit it on that part.
- First lash the great ones, but if thou be wise, In generall and doe not speciallize.
- Used in the Ending of Sentence
- You'll get a better flavour from the chicken if you marinate it first.
- I'm sick of having to hand-hold every new person we hire. Why can't we train them first?
- Spencer read Greats at Oxford, taking a starred first.
- Used in the Middle of Sentence
Definition of first in English Dictionary
- Part-of-Speech Hierarchy
- Adjectives
- Uncomparable adjectives
- Uncomparable adjectives
- Adverbs
- Conjunctive adverbs
- Sequence adverbs
- Sequence adverbs
- Uncomparable adverbs
- Conjunctive adverbs
- Morphemes
- Suffixes
- Words by suffix
- Words suffixed with -est
- Words suffixed with -est
- Words by suffix
- Suffixes
- Nouns
- Countable nouns
- Singularia tantum
- Uncountable nouns
- Uncountable nouns
- Countable nouns
- Adjectives
Source: Wiktionary
Grammatically, this word "first" is an adjective, more specifically, an uncomparable adjective. It's also an adverb, more specifically, a conjunctive adverb and an uncomparable adverb. It's also a morpheme, more specifically, a suffixe. It's also a noun, more specifically, a countable noun and a singularia tantum.