probability in WordNet English dictionary

1. 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"
   probability  chance 
   
2. 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"
   probability