
From Wikipedia.
The gluteus maximus is the largest of the gluteus
muscles which are located in the buttock. The other
gluteus muscles include the gluteus medius and the
gluteus minimus, collectively the gluteus muscles
are commonly known as the gluteal muscles. The
gluteus maximus is the most powerful muscle of
the human body.
The gluteus maximus is often referred to as the "butt"
or "rear-end" of a person's anatomy.