Differentiate, v. t.
1. To distinguish or mark by a specific difference; to effect a difference in, as regards classification; to develop differential characteristics in; to specialize; to desynonymize. The word then was differentiated into the two forms then and than. Earle. Two or more of the forms assumed by the same original word become differentiated in signification. Dr. Murray.
2. To express the specific difference of; to describe the properties of (a thing) whereby it is differenced from another of the same class; to discriminate. Earle.
3. (Math.)
To obtain the differential, or differential coefficient, of; as, to differentiate an algebraic expression, or an equation.
1 other Webster entry under this spelling
Differentiate, v. i. (Biol.)
To acquire a distinct and separate character. Huxley.
Shades of meaning
Fernald has no entry of its own for differentiate; he lists it under contrast.
Where he writes about it:
We contrast them when we observe their unlikeness in a general way; we differentiate them when we note the difference exactly and point by point. — from contrast