Nouns

(n)traffic circle, circle, rotary, roundabouta road junction at which traffic streams circularly around a central island“the accident blocked all traffic at the rotary”
(n)synchronous converter, rotary, rotary converterelectrical converter consisting of a synchronous machine that converts alternating to direct current or vice versa

Adjectives

(a)rotaryrelating to or characterized by rotation“rotary dial”
(s)circular, rotary, orbitaldescribing a circle; moving in a circle“the circular motion of the wheel”