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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).
Variants of sigmoid
Origin of sigmoid
Greek sigmoeidēs, from sigma; from a common form of sigma shaped like the Roman letter C
First Known Use: 1670
Rhymes with sigmoid
android, avoid, chancroid, colloid, conoid, crinoid, cuboid, cycloid, deltoid, dendroid, devoid, discoid, factoid, fibroid, fungoid, ganoid, globoid, hydroid, hypnoid, keloid, mastoid, mucoid, ovoid, prismoid, pygmoid, rhizoid, rhomboid, schizoid, scombroid, spheroid, steroid, styloid, tabloid, thalloid, thyroid, toroid, toxoid, trochoid, typhoid, Veddoid, viroid
Learn More about sigmoid
Medical Dictionary: Definition of "sigmoid"
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