What is the meaning of Modulation?

Variation (especially softening or toning down) of brightness, form, etc.; an instance of this.
Variation in the activity or form of a cell in response to changes in the environment; an instance of this.
Chiefly preceded by a descriptive word: modification of an electromagnetic wave or other oscillating carrier wave to apply a signal to it; an instance of this; also, the extent to which such a wave is modified; and the modified wave or signal.
1. Variation of the intensity, pitch, and tone of the sound of a musical instrument or voice; inflection; an instance of this.
3. Changing of the key in a piece of music; also, the effect achieved by this as an element of harmony; an instance of this.
The contrast between the thick and thin parts of the strokes of a typeface.

Variation (especially softening or toning down) of brightness, form, etc.; an instance of this.

Variation in the activity or form of a cell in response to changes in the environment; an instance of this.

Chiefly preceded by a descriptive word: modification of an electromagnetic wave or other oscillating carrier wave to apply a signal to it; an instance of this; also, the extent to which such a wave is modified; and the modified wave or signal.

Variation of the intensity, pitch, and tone of the sound of a musical instrument or voice; inflection; an instance of this.
Changing of the key in a piece of music; also, the effect achieved by this as an element of harmony; an instance of this.

Variation of the intensity, pitch, and tone of the sound of a musical instrument or voice; inflection; an instance of this.

Changing of the key in a piece of music; also, the effect achieved by this as an element of harmony; an instance of this.

The contrast between the thick and thin parts of the strokes of a typeface.

Changing of a thing from one form to another; an instance of this.

Harmonious use of language in poetry or prose.
Modification of the parts of a classical Greek or Roman building to achieve appropriate proportions by measuring in modules (“standard units of measure, usually the diameter or radius of a column at the base of a shaft”).
1. Any of the musical notes in ecclesiastical modes of music on which a melodic phrase had to begin and end.
2. Arrangement or composition, or performance, of music in a certain key or mode; also a series of musical notes, chord, or tune analyzed according to a key or mode.
3. Making music or singing; a melody, a tune; also , a musical note.

Modification of the parts of a classical Greek or Roman building to achieve appropriate proportions by measuring in modules (“standard units of measure, usually the diameter or radius of a column at the base of a shaft”).

Any of the musical notes in ecclesiastical modes of music on which a melodic phrase had to begin and end.
Arrangement or composition, or performance, of music in a certain key or mode; also a series of musical notes, chord, or tune analyzed according to a key or mode.
Making music or singing; a melody, a tune; also , a musical note.

Any of the musical notes in ecclesiastical modes of music on which a melodic phrase had to begin and end.

Arrangement or composition, or performance, of music in a certain key or mode; also a series of musical notes, chord, or tune analyzed according to a key or mode.

Making music or singing; a melody, a tune; also , a musical note.

inflection (change in pitch or tone of voice)

modulation (change in key)

Source: wiktionary.org

See also