Things that show a difference or act in different ways can be described as differential. You and your sister may get differential benefits from eating a vegetarian diet.
You're most likely to come across the adjective differential in scholarly or scientific writing — it's really just a more formal way to say "different" or "differing." Sociological studies or articles often describe differential circumstances or outcomes, like the differential effects on various children of being raised with one parent. The Latin differentia is at the root of differential — it means "diversity or difference," and it comes from differre, "to set apart."
Primary Meanings of differential
a quality that differentiates between similar things
relating to or showing a difference
a bevel gear that permits rotation of two shafts at different speeds; used on the rear axle of automobiles to allow wheels to rotate at different speeds on curves
n the result of mathematical differentiation; the instantaneous change of one quantity relative to another; df(x)/dx
the rate of change (at a point) of the angle between a curve and a tangent to the curve
partial, partial derivative
the derivative of a function of two or more variables with respect to a single variable while the other variables are considered to be constant