An Etymological Dictionary of Astronomy and Astrophysics

1. Noun.
   1a) General: A difference or the amount of difference, as in rate, cost, quantity, degree, or quality, between things that are comparable.
   

1b) Math.: An infinitesimally small change in a variable; a function of two variables that is obtained from a given function, y = f(x), and that expresses the increment in the given function as the derivative of the function, f’(x), times the increment in the independent variable, written as dy = f’(x) dx.

1c) Electronics: Referring to a circuit, device, or machine whose principle of operation depends on the difference between two opposing effects.

2. Adjective.
   2a) General: Of, relating to, or constituting a difference.
   

2b) Physics: Pertaining to or involving the difference of two or more motions, forces, etc.

2c) Math.: Pertaining to or involving a → derivative or derivatives.

Etymology (EN): From M.L. differentialis, from differenti(a),
→ difference, + → -al.

Etymology (PE): Degarsâné, from degarsân, → different + noun suffix -é.