Probabilities

How to spell probabilities

13 letters · 5 syllables

How to pronounce probabilities

Say the part in capitals loudest.

What does probabilities mean?

1. nounThe measures of how likely various outcomes are, often expressed as numbers between zero and one.

Probabilities in a sentence

• The analyst calculated the probabilities of each possible outcome before advising the board.

• Weather models assign different probabilities to rain across the weekend.

Where does probabilities come from?

Language of origin: Latin

This word traces back to the Latin probabilitas, meaning 'credibility' or 'likelihood', which was built on the adjective probabilis, 'provable, credible, likely to be approved'. That adjective in turn came from the verb probare, 'to test, examine, or prove', whose deeper root is probus, meaning 'good, upright, honest'. The same probare root gives us 'prove', 'probe', and 'approve', all carrying that old sense of putting something to the test. English took 'probability' in through Old French and Latin during the 1400s, at first meaning simply the quality of being believable, and only later did mathematicians of the seventeenth century narrow it to the numerical chance of an event. The tricky spelling comes from the long stack of weak, unstressed syllables after the stressed -BIL-, where the two separate i sounds and the soft -ity ending blur together in speech.

How the word is built

• prob- (from probare: to prove or test)
• -abil- (able to be)
• -ity (noun-forming suffix)
• -es (plural)