monotone

The story

1. Latin · derived frommonotonus“unvarying in tone”
2. English todaymonotone

From the post-Classical Latin monotonus (“unvarying in tone”) or its etymon the Ancient Greek μονότονος (monótonos, “steady”, “unwavering”); compare cognate adjectives, namely the French monotone, the German monoton, the Italian monotono, and the Spanish monótono, as well as the slightly earlier English noun monotony and adjective monotonical.