Engineering and Machinery

• Rotary engine, a type of internal combustion engine from the early 20th century

• * Rotary engine sometimes means the Wankel engine in particular

• A rotary latch

• Rotary milking shed, a type of milking shed used in the dairy industry

• Rotary snowplow, one type of railroad snowplow used especially for deep snow removal

• Rotary table (drilling rig), a device used to apply directional force to a drill string

• Rotary tiller, a motorised cultivator

• Rotary woofer, a type of loudspeaker capable of producing very low frequency sound

• Rotary wing aircraft

Telecommunications

• Rotary dial, a rotating telephone dial

• Rotary system, a type of pre-electronic telephone switch

Companies

• Rotary International, or Rotary Club, a service organization

• Rotary Watches, a Swiss watchmaker

Other

• Rotary International, a worldwide organization of service clubs

• Rotary (intersection), a type of circular roadway intersection, distinct from a roundabout or traffic circle, in which traffic streams around a central island