Definition of sigmoid in English:


Syllabification: sig·moid
Pronunciation: /ˈsigmoid


  • 1Curved like the uncial sigma (C); crescent-shaped.
    More example sentences
    • To isolate deviations from typical tree growth, we developed a model based on the amount of shoot elongation, which over equal time intervals approximates a sigmoid curve.
    • The growth curve of the fruit of Marisol clementine fitted a single sigmoid curve well.
    • Usually, a time course of plant growth follows a sigmoid curve, which can be described by a logistic function.
  • 2S-shaped.
    More example sentences
    • First, the cumulative adoption of an innovation over time follows an S-shaped or sigmoid curve.
    • ‘The river flows in long sigmoid Curves,’ he wrote, ‘through an alluvial valley of no great width.’
    • A series of unsuccessful attempts at scheduling surgery for her sigmoid colectomy followed because of complications with her neutrophil count and hospitalization for new onset atrial fibrillation.


Anatomy Back to top  
  • short for sigmoid colon.
    More example sentences
    • The sigmoid may lie in the abdomen just inferior to the splenic flexure of the transverse colon, or in the right iliac fossa.
    • Although sigmoid volvulus can resolve spontaneously, nonoperative management begins with fluid resuscitation and antibiotics, followed by barium enema detorsion of the sigmoid.
    • The most frequently involved site is the sigmoid.



Pronunciation: /sigˈmoidəl/
More example sentences
  • A blood sample drawn at presentation was examined; unlike all other specimens studied, there was a sigmoidal increase at 550 nm, but not at 610 or 700 nm.
  • The majority of the curves display a simple sigmoidal pH dependence; however, several residues exhibit more complex shapes.
  • On the other hand, the curve describing the aggregation equilibrium in the membrane shows that aggregation in this phase is much less favored as compared to water and exhibits a marked sigmoidal shape.


late 17th century: from Greek sigmoeidēs, from sigma (see sigma).

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