Definition of probability in English:

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Pronunciation: /ˌpräbəˈbilədē/

noun (plural probabilities)

1The extent to which something is probable; the likelihood of something happening or being the case: the rain will make the probability of their arrival 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.
1.1A probable or the most probable event: for a time, revolution was a strong probability the probability is that it will be phased in over a number of years
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 favorable cases to the whole number of cases possible: the area under the curve represents probability 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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Syllabification: prob·a·bil·i·ty

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