unison

unison · noun¹

1. Medieval Latin · derived fromūnisonus“having the same sound”
2. Middle French · derived fromunisson
3. Middle English · inherited fromunisoun
4. English todayunison

From Middle English unisoun, from Middle French unisson, from Medieval Latin ūnisonus (“having the same sound”), from ūni- + sonus (“sound”).

UNISON · proper noun²

Since 1993. Created as a play on unison, as the united workers act in unison.

First known use, by meaning

• from 15th c. Identical pitch between two notes or sounds; the simultaneous playing of notes of identical pitch (or separated by one or more octaves).
• from 15th c. A sound or note having the same pitch as another, especially when used as the base note for an interval; a unison string.
• from 17th c. The state of being in harmony or agreement; harmonious agreement or togetherness, synchronisation.