The term "saddle joint" refers to a specific type of joint found in the human body where two bones come together and resemble a horse's saddle. There are several synonyms for this type of joint, including sellar joint, articulation sella, and biaxial joint. Another term commonly used to describe a saddle joint is a condyloid joint, which refers to the articulation between two bones that allows for movement in two different planes. This type of joint is found in several areas of the body, including the thumb, ankle, and spine. The use of these synonyms can be helpful in understanding the structure and function of the saddle joint.