v.
1. tr. a regulate or adjust. b moderate.
2 tr. adjust or vary the tone or pitch of (the speaking voice).
3 tr. alter the amplitude or frequency of (a wave) by a wave of a lower frequency to convey a signal.
4 intr. & tr. Mus. (often foll. by from, to) change or cause to change from one key to another.
Derivatives:
modulation n. modulator n.
Etymology: L modulari modulat- to measure f. modus measure