Definitions

1. noun

A muscle in the human body, specifically the broad, flat muscle in the lower back that extends from the lower border of the 12th rib to the iliac crest and the lumbodorsal fascia.

“The quadratus lumborum muscle helps to stabilize the lumbar spine and facilitate rotational movements of the torso.”

2. adjective

Having four parts or surfaces.

“The quadratus crystal has four distinct facets that reflect light in a unique way.”