The hip bone is one of the most important bones in the human body. It is formed by the fusion of three bones and is located between the pelvis and the thigh. However, there are several synonyms that can be used to refer to the hip bone. One commonly used synonym is the coxal bone, which is derived from the Latin word "coxa" meaning hip. Another term is the innominate bone, which literally means "nameless bone" because it was thought to have no specific shape. The term pelvis also refers to the hip bone, but it is the entire structure that includes the hip bone, sacrum, and coccyx. Despite the different terms, all of them refer to the same structure in the human body.