differentia /(?)/

dif·fer·en·ti·a

differentia

n.

pl. Differentiæ

  1. The formal or distinguishing part of the essence of a species, by which it is distinguished from other members of its genus; the characteristic attribute of a species; specific difference; as, a proper definition must have both genus and differentia. (Logic)
  2. the set of characteristics distinguishing an entity from related entities.