Rotary and Rotatory are synonymous words that can be used interchangeably to describe something that moves in a circular motion. These terms are commonly used in technology, engineering, and science to describe machines and devices that rotate. The term rotary is commonly used to describe rotary engines, such as those used in airplanes, while rotatory is used to describe objects that rotate around a fixed axis. Both terms are derived from the Latin word "rota", which means wheel or circle. Other synonyms for the word rotaryrotatory include revolving, spinning, turning, whirling, and gyratory, all of which describe circular or rotational movement.