one

The number represented by the Arabic numeral 1; the numerical value equal to that cardinal number.

In some religions, there is more than one god.

In many cultures, a baby turns one year old a year after its birth.

The first positive number in the set of natural numbers.

The cardinality of the smallest nonempty set.

The ordinality of an element which has no predecessor, usually called first or number one.

One thing (among a group of others); one member of a group.

Any one of the boys.

Every one of the bank’s employees.

The first mentioned of two things or people, as opposed to the other.

She offered him an apple and an orange; he took (the) one and left the other.

I am one of the few women who've climbed Everest.

Any person (applying to people in general).

One’s guilt may trouble one, but it is best not to let oneself be troubled by things which cannot be changed.  One shouldn’t be too quick to judge.

My neighbor talks to one like a teacher.

Any person, entity or thing.

"driver", noun: one who drives.

The digit or figure 1.

This effectively allows switching on and off of the flow of current, so it is either conducting or not conducting, creating the binary system of zeroes and ones used in digital computers.

Used to briefly refer to a noun phrase understood by context

I need some ones to make change.

Used to briefly refer to a noun phrase understood by context

It was already one in the morning; the rain pattered dismally against the panes, and my candle was nearly burnt out, when, by the glimmer of the half-extinguished light, I saw the dull yellow eye of the creature open; it breathed hard, and a convulsive motion agitated its limbs.

The ophthalmic surgeon attends Tuesdays and Saturdays, at half-past one.

Used to briefly refer to a noun phrase understood by context

Used to briefly refer to a noun phrase understood by context

Did you hear the one about the agnostic dyslexic insomniac?