1. Electronics.frequency modulation: a method of impressing a signal on a radio carrier wave by varying the frequency of the carrier wave.
2. Radio.a system of radio broadcasting by means of frequency modulation.
3. of, pertaining to, or utilizing such a system. Cf. AM.
(in prescriptions) make a mixture.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.