adj. & n.
--adj. acting by rotation (rotary drill; rotary pump).
--n. (pl. -ies)
1. a rotary machine.
2 US a traffic roundabout.
3 (Rotary) (in full Rotary International) a worldwide charitable society of businessmen, orig. named from members entertaining in rotation.
Phrases and idioms:
Rotary club a local branch of Rotary. rotary-wing (of an aircraft) deriving lift from rotary aerofoils.
Etymology: med.L rotarius (as ROTA)