A rotatory joint is a type of joint that enables rotational movement around its axis. There are several synonyms used to describe this type of joint, depending on the context of use. For example, pivot joint is a common term used to refer to a rotatory joint. Generally found in the neck, pivot joints allow side-to-side or up-and-down movement. Similarly, a ball-and-socket joint is another type of rotatory joint that enables rotation in multiple directions. Hinge joint is another synonym for rotatory joint often used in the context of movement of the elbow which only allows flexion and extension. Overall, these synonyms help in describing the different types of rotatory joints found in the human body.