While

a while: A length of time

Usage:
I haven’t seen him for a while (= for a long time).
I’ll be fine in a while (= soon).
I only stayed for a short while.
You were there quite a while (= a long time), weren’t you?

Excerpts from soaps, novels and films:

Bold and the beautiful

“Nick: You play poker?

Taylor: It’s been a while, but I know the basics.”