1. Having the shape of the letter S.
2. Of or relating to the sigmoid colon.

[Greek sīgmoeidēs : sīgma, sigma; see sigma + -oeidēs, -oid.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.