The story
Deverbal from set off.
First known use, by meaning
- from 17th c. Something used to improve the appearance; a decoration, an ornament.
- from 18th c. The act of setting off on a journey; a departure, a start.
- from 18th c. A counterclaim; a distinct claim filed or set up by the defendant against the plaintiff's demand.
- from 18th c. Anything set off against another thing; a compensation, a counterbalancing circumstance.
Etymology from Wiktionary, CC BY-SA 4.0.