Certainty vs. certitude

What does certainty mean?

Certainty is a noun which means conviction that something is true or the quality of being reliably true.

For example:

• I know with absolute certainty that she’ll be late tonight.

What does certitude mean?

Certitude is a noun which means the conviction that something is the case.

For example:

• Who ordered the attack may never be answered with certitude.

What’s the difference between certainty and certitude?

Certainty and certitude mean the same thing in many situations. The subtle difference between both words lies in the reason why you think something is certain: certainty is often based on fact while certitude is generally a conviction of feeling or gut instinct.

Of course, facts can be subjective! What I consider factual evidence another may dismiss as heresy.