- sacroiliac⇄adj. 1. of or having to do with the sacrum and the ilium.
Ex. sacroiliac articulation.
2. designating the joint between the sacrum and the ilium. - sacroiliac⇄noun the sacroiliac joint.
Ex. Strictly speaking, the sacroiliac is an area at the base of the spine; everybody has one (Atlantic). - sacroiliac⇄sacroiliac, adjective, noun.