1) Difference 
In Scholastic logic, differentia is one of the predicables. It is that part of a definition which is predicable in a given genus only of the definiendum; or the corresponding `metaphysical part` of the object. ==Origin of the notion== The concept of differentia was, as a matter of fact, already employed by Plato when he conceived his method of d.....
property which distinguishes one from another
• (n.) The formal or distinguishing part of the essence of a species; the characteristic attribute of a species; specific difference.
Dif`fer·en'ti·a noun ; plural Differentiæ . [ Latin See Difference .] (Logic) The formal or distinguishing part of the essence of a species; the characteristic attribute of a species; specific difference. 
[n] - a distinguishing characteristic esp in different species of a genus
differentia (s), differentiae (pl) The quality or condition that distinguishes one species from all the others of the same genus or class.
noun distinguishing characteristics (especially in different species of a genus)
the character or attribute by which one species is distinguished from all others of the same genus. · the character or basic factor by which one entity is distinguished from another.