- (uncountable) Certainty is the state of being 100% sure.
- It's a little too early to say that with absolute certainty.
- The doctor could not say what was wrong with any degree of certainty.
- (countable) If something is a certainty, it is sure to happen.
- The expected change became a certainty two weeks ago.
- We need to accept the certainties of aging, illness, and death.