Definition

1. Noun:
   • The quality or state of being probable; likelihood: "Probability" refers to the chance or likelihood that a particular event will happen.
   • A probable or most probable event: "Probability" can also refer to the event or outcome that is most likely to occur.
   • (Mathematics) A numerical measure of likelihood: In mathematics and statistics, "probability" is a number between 0 and 1 expressing the ratio of favorable outcomes to all possible outcomes in a defined situation.

Examples of Usage

• Noun:
  • The probability of rain tomorrow is high. (The likelihood that it will rain tomorrow is great.)
  • In all probability, the meeting will be postponed. (It is very likely that the meeting will be postponed.)
  • The probability of drawing an ace from a standard deck is 1/13. (The mathematical chance of selecting an ace is one in thirteen.)

Advanced Usage

• "in all probability": very likely, almost certainly.
  • In all probability, the project will be completed on schedule.
• "balance of probability": (in law) the standard of proof which must be met for a fact to be considered more likely true than not.
  • The case was decided on the balance of probability.

Variants and Related Words

• Probable (adj): likely to happen or be the case.
  • Rain is probable this afternoon.
• Probabilistic (adj): of, relating to, or based on probability.
  • The model makes probabilistic predictions.
• Probabilistically (adv): in a way that involves probability.
  • The system was designed to function probabilistically.

Synonyms

• Likelihood: The chance of something happening.
• Odds: The ratio of the probability of an event happening to it not happening.
• Chance: The occurrence of events without an apparent cause; luck, or a possibility.

Related Phrases

• Probability theory: The branch of mathematics concerned with probability.
  • She studied probability theory in her statistics course.
• Probability distribution: (Statistics) A function that gives the probabilities of occurrence of different possible outcomes.
  • The normal curve is a common probability distribution.

Idioms

• Against all probability: Contrary to what seems likely.
  • Against all probability, the underdog team won the championship.

Noun

1. the quality of being probable; a probable event or the most probable event
   • for a while mutiny seemed a probability
   • going by past experience there was a high probability that the visitors were lost
2. a measure of how likely it is that some event will occur; a number expressing the ratio of favorable cases to the whole number of cases possible
   • the probability that an unbiased coin will fall with the head up is 0.5