1550s, "act of rotating or turning, action of moving round a center," from Latin rotationem (nominative rotatio) "a turning about in a circle," noun of action from past-participle stem of rotare "turn round, revolve, whirl about, roll," from the same source as rota "wheel" (see rotary).
Sense of "a recurring series or period" is by 1610s. Used earlier in alchemy, "transmutation of the four elements into one another" (late 15c.).
updated on October 03, 2021