modulation

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or process of modulating.
• noun The state of being modulated.
• noun A passing or transition from one key or tonality to another.
• noun The result of such a transition.
• noun A change in stress, pitch, loudness, or tone of the voice; an inflection of the voice.
• noun An instance of such a change or an inflection.
• noun The harmonious use of language, as in poetry or prose.
• noun Electronics The variation of a property of an electromagnetic wave or signal, such as its amplitude, frequency, or phase.

from The Century Dictionary.

• noun The act of modulating
• noun The act of inflecting the voice or any instrument in a musical manner.
• noun The modification of the voice or of utterance to express various shades of meaning or emotion.
• noun A state or condition reached by a process of modulating, modifying, or varying.
• noun In Gregorian music, one of the tones in a mode with which every phrase of a melody in that mode must begin and end.
• noun In modern music, the act, process, or result of changing, in the course of a piece, from one key (tonality) to another, so that a new tone becomes the key-note and the relative significance of all the tones common to both tonalities is altered.
• noun A musical composition exemplifying modulation.
• noun Sound modulated; melody.
• noun In architecture, the proportion of the different parts of an order according to a module.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of modulating, or the state of being modulated.
• noun rare Sound modulated; melody.
• noun (Mus.) A change of key, whether transient, or until the music becomes established in the new key; a shifting of the tonality of a piece, so that the harmonies all center upon a new keynote or tonic; the art of transition out of the original key into one nearly related, and so on, it may be, by successive changes, into a key quite remote. There are also sudden and unprepared modulations.
• noun (Electronics) The alteration of hte amplitude, intensity, frequency, or phase (of the carrier wave of a radio signal) at intervals, so as to represent information to be transmitted.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The process of applying a signal to a carrier, modulating.
• noun Methods of modulating.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• 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 the act of modifying or adjusting according to due measure and proportion (as with regard to artistic effect)
• noun a musical passage moving from one key to another
• noun rise and fall of the voice pitch
• noun a manner of speaking in which the loudness or pitch or tone of the voice is modified