Sometimes sig·moi·dal [sig-moi-dl] /sɪgˈmɔɪ dl/.

Origin of sigmoid

First recorded in 1660–70, sigmoid is from the Greek word sigmoeidḗs shaped like a sigma. See sigma, -oid
Related formssig·moi·dal·ly, adverbpost·sig·moid, adjectivepost·sig·moi·dal, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for sigmoidal

Historical Examples of sigmoidal

British Dictionary definitions for sigmoidal


adjective Also: sigmoidal
  1. shaped like the letter S
  2. of or relating to the sigmoid colon of the large intestine

Word Origin for sigmoid

C17: from Greek sigmoeidēs sigma-shaped
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for sigmoidal



"shaped like a C" (1660s) or "shaped like an S" (1786), from sigma (q.v.) + -oid. Especially of the flexure of the colon (1891).

Online Etymology Dictionary, © 2010 Douglas Harper

sigmoidal in Medicine


  1. Having the shape of the letter S.
  2. Of or relating to the sigmoid flexure of the colon.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.