variation
The act of varying; a partial change in the form, position, state, or qualities of a thing.
Other meanings
A related but distinct thing.
“When the process didn't work, we tried a variation.”
The angular difference at the vessel between the direction of true north and magnetic north.
Where this comes from
This definition is adapted from “variation” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.