Excurvate is a term used in geology and biology to refer to a curve that is convex towards the outside of the object. Essentially, it means that the curve moves outward from the center of the object. There are several synonyms for excurvate, including convex, bulging, protruding, and arched. All of these words describe a curve that is similar in shape to excurvate, but they may be used in different contexts. For example, convex is often used in mathematical contexts to describe a shape or surface that bulges outward. Arched is often used to describe structures such as doorways or windows.