sigmoid

adjective
sig·​moid | \ ˈsig-ˌmȯid How to pronounce sigmoid (audio) \
variants: or less commonly sigmoidal \ sig-​ˈmȯi-​dᵊl How to pronounce sigmoid (audio) \

Definition of sigmoid

1a : curved like the letter C
b : curved in two directions like the letter S
2 : of, relating to, or being the sigmoid colon

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Other Words from sigmoid

sigmoidally \ sig-​ˈmȯi-​dᵊl-​ē How to pronounce sigmoid (audio) \ adverb

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The shape sense of sigmoid is most often used in scientific contexts to describe an s-shaped curve on a graph. Usually, though, sigmoid is used in contexts relating to the sigmoid colon-the contracted and crooked part of the colon immediately above the rectum. Sigmoid comes from sigma, the name of the 18th letter of the Greek alphabet. At one time sigma had a common form that was shaped like the Roman letter C (hence sense 1a), but sigma is equivalent to the English letter S (hence sense 1b).

Examples of sigmoid in a Sentence

Recent Examples on the Web Francis had developed a diverticular stenosis, or narrowing, of the sigmoid portion of the large intestine. BostonGlobe.com, 6 July 2021 Francis had developed a diverticular stenosis, or narrowing, of the sigmoid portion of the large intestine. Fox News, 5 July 2021 To do this, the computer breaks down the mystery function into a number of layers of unknown functions called sigmoid functions. Quanta Magazine, 3 Dec. 2015

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sigmoid.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of sigmoid

1670, in the meaning defined at sense 1a

History and Etymology for sigmoid

Greek sigmoeidēs, from sigma; from a common form of sigma shaped like the Roman letter C

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Time Traveler for sigmoid

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The first known use of sigmoid was in 1670

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Last Updated

15 Jul 2021

Cite this Entry

“Sigmoid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sigmoid. Accessed 24 Jul. 2021.

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More Definitions for sigmoid

sigmoid

adjective
sig·​moid | \ ˈsig-ˌmȯid How to pronounce sigmoid (audio) \

Medical Definition of sigmoid

 (Entry 1 of 2)

1a : curved like the letter C
b : curved in two directions like the letter S
2 : of, relating to, or being the sigmoid colon of the intestine sigmoid lesions

sigmoid

noun

Medical Definition of sigmoid (Entry 2 of 2)

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