the number 1

 

pronoun

 

particular person/thing used to refer to a particular person or thing in a group that has already been talked about

I've just made some scones, do you want one?

 

general any person in general

One ought to respect one's parents.

 

determiner

 

particular person/thing used to refer to a particular person or thing in a group

One drawback is the cost of housing in the area.

 

future time used to refer to a time in the future which is not yet decided

We must have a drink together one evening.

 

time in past at a particular time in the past

I first met him one day in the park.

 

only only

He's the one person you can rely on in this place.

 

with adjective used to emphasize an adjective

That's one big ice cream you've got there!