Meaning

noun a musical passage moving from one key to another

noun (electronics) the transmission of a signal by using it to vary a carrier wave; changing the carrier's amplitude or frequency or phase

noun rise and fall of the voice pitch

originFrom Late Middle English modulacion, modulacioun (“act of making music or singing; harmony; melody, song”), from Middle French modulation (modern French modulation), and directly from its etymon Latin modulātiō (“regular or rhythmical measure, modulation; inflection of tone; (architecture) calculation of measurements from a standard unit; (Late Latin) act of making music or singing; melody,…

Etymology from Wiktionary, CC BY-SA 3.0