probability

[ prob-uh-bil-i-tee ]

noun

, plural prob·a·bil·i·ties.

1. the quality or fact of being probable.
2. a strong likelihood or chance of something:

   The probability of the book's success makes us optimistic.

3. a probable event, circumstance, etc.:

   Our going to China is a probability.

4. Statistics.
   1. the relative possibility that an event will occur, as expressed by the ratio of the number of actual occurrences to the total number of possible occurrences.
   2. the relative frequency with which an event occurs or is likely to occur.

probability

/ ˌprɒbəˈbɪlɪtɪ /

noun

1. the condition of being probable
2. an event or other thing that is probable
3. statistics a measure or estimate of the degree of confidence one may have in the occurrence of an event, measured on a scale from zero (impossibility) to one (certainty). It may be defined as the proportion of favourable outcomes to the total number of possibilities if these are indifferent ( mathematical probability ), or the proportion observed in a sample ( empirical probability ), or the limit of this as the sample size tends to infinity ( relative frequency ), or by more subjective criteria ( subjective probability )

probability

/ prŏb′ə-bĭl′ĭ-tē /

1. A number expressing the likelihood of the occurrence of a given event, especially a fraction expressing how many times the event will happen in a given number of tests or experiments. For example, when rolling a six-sided die, the probability of rolling a particular side is 1 in 6, or 1 6 .

probability

1. A number between zero and one that shows how likely a certain event is. Usually, probability is expressed as a ratio : the number of experimental results that would produce the event divided by the number of experimental results considered possible. Thus, the probability of drawing the ten of clubs from an ordinary deck of cards is one in fifty-two (1:52), or one fifty-second.

Other Words From

• nonprob·a·bili·ty noun plural nonprobabilities
• super·proba·bili·ty noun plural superprobabilities

Word History and Origins

Origin of probability¹

From the Latin word probābilitās, dating back to 1545–55. See probable, -ity

Idioms and Phrases

Idioms

1. in all probability, very probably; quite likely:

   The factory will in all probability be relocated.

More idioms and phrases containing probability

see in all probability .

Example Sentences

"Sub-diurnal forecasting, meaning less than 24 hours, is mainly used for evacuation. This method gives us more accurate forecast probabilities compared to those that make predictions daily or over multiple days," Ahmed says.

From Science Daily

Jason Woodman of Mid and West Wales Fire and Rescue Service told the inquest that, "based on the balance of probabilities", the fire had started in that area.

From BBC

The probability of their models was based on the dynamics of these pheromones.

From Science Daily

Week two: Against the Bengals, the Chiefs' win probability was 15.5% in the fourth quarter, before Harrison Butker won it with a field goal as time expired.

From BBC

A sobering independent review two months later determined there was “near zero probability” of Mars Sample Return making its proposed 2028 launch date, and “no credible” way to fulfill the mission within its current budget.

From Los Angeles Times

Related Words

• anticipation
• chance
• contingency
• expectation
• feasibility
• odds
• possibility
• prospect