Wiktionary
n. (context anatomy English) a broad, thin muscle, situated on the side of the pelvis, that forms part of the pelvic floor. In humans it supports the viscera in pelvic cavity and in quadruped animals with tails it is the muscle used to wag the tail.
Wikipedia
The levator ani is a broad, thin muscle, situated on either side of the pelvis. It is formed from three muscle components: the puborectalis, the pubococcygeus muscle (of which the puborectalis is part of) and the iliococcygeus muscle.
It is attached to the inner surface of each side of the lesser pelvis, and these unite to form the greater part of the pelvic floor. The coccygeus muscle completes the pelvic floor which is also called the pelvic diaphragm.
It supports the viscera in the pelvic cavity, and surrounds the various structures that pass through it.