Variation

Noun

1. The act of varying; a partial change in the form, position, state, or qualities of a thing.
2. A related but distinct thing.

   "When the process didn't work, we tried a variation."

3. The angular difference at the vessel between the direction of true north and magnetic north.
4. A line of play that differs from the original.
5. A technique where material is repeated with alterations to the melody, harmony, rhythm, timbre, texture, counterpoint or orchestration; but with some invariant characteristic, e.g. a ground bass.