The semilunar bone, also known as the triquetral bone, is a small bone found in the wrist. It is one of the eight carpal bones that make up the wrist joint. The word "semilunar" refers to the bone's shape, which is crescent or half-moon shaped. While the term "semilunar bone" is commonly used, it is sometimes called the triquetral bone, triangular bone, pyramidal bone, or cuneiform bone. These synonyms refer to the bone's shape or its location within the wrist. The semilunar bone plays an important role in the movement and stability of the wrist joint and is crucial for proper functioning of the hand.