- The state of being certain; the quality of being sure or certain.
- A fact or truth that is known or certain.
From old french certeine, from latin certus ("fixed, settled, sure, certai.n")
- She spoke with certainty about the outcome of the election.
- The scientist expressed certainty that the new theory was correct.
- The outcome of the game was a certainty.
- The certainty of death and taxes is a famous quote from Benjamin Franklin.
- There is no certainty in life, only probability.