Definition of modulations:
(n) :
(music) (uncountable) Variation of the intensity, pitch, and tone of the sound of a musical instrument or voice; inflection; (countable) an instance of this.
(n) :
(music) (uncountable) Changing of the key in a piece of music; also, the effect achieved by this as an element of harmony; (countable) an instance of this.
(n) :
(uncountable) Modification or regulation of something to achieve an appropriate measure or proportion; (countable) an instance of this.
(n) :
(engineering, physics, uncountable) Chiefly preceded by a descriptive word: modification of an electromagnetic wave or other oscillating carrier wave to apply a signal to it; (countable) an instance of this; also, the extent to which such a wave is modified; and the modified wave or signal.
(n) :
(biology, uncountable) Variation in the activity or form of a cell in response to changes in the environment; (countable) an instance of this.
(n) :
(art, uncountable) Variation (especially softening or toning down) of brightness, form, etc.; (countable) an instance of this.