Definition of probability in English:

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Pronunciation: /prɒbəˈbɪlɪti/

noun (plural probabilities)

[mass noun]
1The quality or state of being probable; the extent to which something is likely to happen or be the case: the rain will make the probability of a postponement even greater
More example sentences
  • They will continue to kidnap because probability shows that the chance of being caught and prosecuted in Trinidad is slim.
  • The laws of probability say it cannot happen but Maine Road is still too fresh in the minds of Minstermen everywhere for it to be ignored just yet.
  • He agreed with the coroner that on the balance of probability it was likely someone else had been in the graveyard when the stone fell on Adam.
1.1 [count noun] A probable or the most probable event: for a time revolution was a strong probability
More example sentences
  • By ‘it is clear’, I mean that the facts establish this as a strong probability.
  • If she is young and attractive, the court may consider her remarriage to be a strong probability.
  • Give us some sense about the probabilities that you are talking about here and what you are looking for.
probable event, prospect, possibility, good/fair/reasonable bet
1.2 Mathematics The extent to which an event is likely to occur, measured by the ratio of the favourable cases to the whole number of cases possible: the area under the curve represents probability [count noun]: a probability of 0.5
More example sentences
  • In the field of mathematics he worked on probability, recurring decimals and the theory of equations.
  • Among seven people, there is about a 60 percent probability that two will have birthdays within a week of each other.
  • When there are twice as many attackers as defenders, the winning probability exceeds 80 percent.


in all probability

Used to convey that something is very likely: he would in all probability make himself known
More example sentences
  • Matches between these two teams in recent years have always been close and in all probability that's how it's going to be again on this occasion.
  • There is no need to ask to see the official personally and to take up his time in this way; if appropriate, he will send a message of thanks at a later date, in all probability.
  • Women with low BMI value and anaemia in the reproductive age will, in all probability, have low birth weight infants.


Late Middle English: from Latin probabilitas, from probabilis 'provable, credible' (see probable).

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