psoas

 
Pronunciation: /ˈsəʊas/
(also psoas major)

noun

Anatomy
  • each of a pair of large muscles which run from the lumbar spine through the groin on either side and, with the iliacus, flex the hip. A second muscle, the psoas minor, has a similar action but is often absent.

Origin:

late 17th century: from Greek, accusative plural of psoa, interpreted as singular