| 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.
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| 5. | in all probability, very probably; quite likely: The factory will in all probability be relocated. |
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.
| probability (prŏb'ə-bĭl'ĭ-tē) Pronunciation Key
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 . |
in all probability
Also, in all likelihood. Most likely, almost certainly. For example, In all probability we'll be home for Christmas. This expression was first recorded in 1617, the variant in 1664.