The pelvis is a bony structure located in the lower abdomen and is composed of several parts. The sacrum, which is six letters long, is a triangular bone at the base of the spine that connects to the HIP bones. The HIPBONE, seven letters long, is a curved bone that forms the sides and back of the pelvis. The HIP, three letters long, is the joint between the femur and the pelvis. Lastly, the ILIUM, five letters long, is the uppermost and largest bone of the pelvis.