sigmoid

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

Keep scrolling for more

Other Words from sigmoid

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

Did You Know?

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 To do this, the computer breaks down the mystery function into a number of layers of unknown functions called sigmoid functions. Quanta Magazine, "Big Data’s Mathematical Mysteries," 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.

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

Keep scrolling for more

Learn More about sigmoid

Time Traveler for sigmoid

Time Traveler

The first known use of sigmoid was in 1670

See more words from the same year

Listen to Our Podcast about sigmoid

Statistics for sigmoid

Cite this Entry

“Sigmoid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sigmoidal. Accessed 25 Feb. 2020.

Keep scrolling for more

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)

More from Merriam-Webster on sigmoid

Rhyming Dictionary: Words that rhyme with sigmoid

Comments on sigmoid

What made you want to look up sigmoid? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

See Definitions and Examples »

Get Word of the Day daily email!

Test Your Vocabulary

More Confusing Words—Quiz

  • cats on impossible timber
  • The magician ______ moved the selected card to the top of the deck.
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!