Sigmoid means resembling the lower-case Greek letter sigma (uppercase Σ, lowercase σ, lowercase in word-final position ς) or the Latin letter S. Specific uses include:

  • Sigmoid function, a mathematical function
  • Sigmoid colon, part of the large intestine or colon
  • Sigmoid sinus, two structures that drain blood from the bottom of the brain
  • Sigmoid arteries, a pair/trio of arteries in the lower abdomen

See also

  • Ogee, similar shape, term sometimes used for sigmoids