DF Definition

abbreviation
Defensor Fidei (Defender of the Faith)
American Heritage
Direction finder.
Webster's New World
Federal District (in Mexico)
Webster's New World

Alternative form of DOF. (In the sense Degree(s) of Freedom)

Wiktionary
symbol

(metrology) Symbol for the decifarad, an SI unit of electrical capacitance equal to 10−1 farads.

Wiktionary