distortion

Short definition from Wiktionary

Noun

1. 1
   An act of distorting.
2. 2
   A result of distorting.
3. 3
   A misrepresentation of the truth.
4. 4
   Noise or other artifacts caused in the electronic reproduction of sound or music.
5. 5
   An effect used in music, most commonly on guitars in rock or metal.
6. 6
   An aberration that causes magnification to change over the field of view.