Probability

How to spell probability

11 letters · 5 syllables

How to pronounce probability

Say the part in capitals loudest.

What does probability mean?

1. nounThe measure or likelihood of a particular event happening, often expressed as a number or a chance.

Probability in a sentence

• The weather report put the probability of rain at sixty percent.

• The analyst calculated the probability of the loan being repaid on time.

Where does probability come from?

Language of origin: Latin

This word traces back to the Latin probabilitas, which carried the sense of 'credibility' or 'likelihood', and that noun was built on the adjective probabilis, meaning 'provable, likely, or worthy of approval'. The deeper root is the verb probare, which literally meant 'to test, to examine, or to prove', the same root that gives us 'prove', 'probe', and 'approve'. English took the word in through Old French probabilite during the late 1400s, when it described something credible or believable rather than a precise numerical chance. The mathematical meaning, the measure of how likely an event is, only sharpened in the 1600s as scholars began studying games of chance and statistics. Keeping the original probare in mind helps with the spelling, since the steady -prob- opening and the smooth -ability ending both come straight from that 'prove worthy' ancestry.

How the word is built

• prob- (from Latin probare: to prove, test)
• -able (capable of)
• -ity (state or quality of)