conditional probability

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The probability that an event will occur, given that one or more other events have occurred.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The probability that an event will take place given the restrictive assumption that another event has taken place, or that a combination of other events has taken place. (Mathematically, the definition would be that the conditional probability of B given A is equal to the joint probability of A and B divided by the probability of A.)

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the probability that an event will occur given that one or more other events have occurred