- modulation
- late 14c., "act of singing or making music," from O.Fr. modulation "act of making music," from L. modulationem (nom. modulatio) "rhythmical measure, singing and playing, melody," from modulatus, pp. of modulari "regulate, measure off properly," from modulus (see module). Meaning "act of regulating according to measure or proportion" is from 1530s. Musical sense of "action of process of changing key" is first recorded 1690s.