a combining form representing sacrum in compound words: sacroiliac.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
word-forming element meaning "of or involving the sacrum, the bone at the base of the spine. E.g. sacro-iliac.
Online Etymology Dictionary, © 2010 Douglas Harper
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.