Definition from Wiktionary, the free dictionary
specificity (plural specificities)
- The state of being specific rather than general.
- (statistics) The probability, in a binary test, of a true negative being correctly identified.
- (medicine) The extent to which a particular diagnostic test is specific for a given condition.
- specificness (much less common)
Coordinate terms 
- (statistics, binary probability): sensitivity
the state of being specific rather than general
a probability in a binary test of a true negative being correctly identified