modulation

Definition
(noun) a musical passage moving from one key to another Definition
(noun) (electronics) the transmission of a signal by using it to vary a carrier wave; changing the carrier's amplitude or frequency or phase Definition
(noun) rise and fall of the voice pitch Definition
(noun) a manner of speaking in which the loudness or pitch or tone of the voice is modified Definition
(noun) the act of modifying or adjusting according to due measure and proportion (as with regard to artistic effect)