1. To form, as sound, to a certain key, or to a certain portion.
2. To vary or inflect in a natural, customary, or musical manner; as, the organs of speech modulate the voice in reading or speaking. Could any person so modulate her voice as to deceive so many? (Broome)
Origin: L. Modulatus, p.p. Of modulari to measure, to modulate, fr. Modulus a small measure, meter, melody, dim. Of modus. See Mode.