rotation [LME]. The Latin rota ‘wheel’ and the verb from it rotare ‘to turn’ is the source of rotation and related words. These include rotund [LME] for something well rounded, and rotunda [E16th] for a round building or room. It is an borrowing of Italian rotonda (camera) ‘round (chamber)’. Round [ME] comes from the same Latin source via French. The worldwide charitable society of business people formed in 1905 known as Rotary International owes its name to the fact that its members hosted events in rotation.