Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
Related to sigmoidal: S curve, sigmoidal kinetics, Sigmoid curve


 (sĭg′moid′) also sig·moi·dal (sĭg-moid′l)
1. Having the shape of the letter S.
2. Of or relating to the sigmoid colon.

[Greek sīgmoeidēs : sīgma, sigma; see sigma + -oeidēs, -oid.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Adj.1.sigmoidal - of or relating to the sigmoid flexure in the large intestine
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
Mentioned in ?
References in periodicals archive ?
cotton residues (100 : 0), 70 : 30, and 50:50, were sigmoidal and were best described ([R.sup.2] = 0.99) by the equation:
The activation function used in the BPN is the sigmoidal function.
The reader's task involves detection and discrimination of a signal, similar to that required in studies of auditory detection or visual discrimination, where data (appropriately scaled) often take sigmoidal form [3-4].
In the absence of added metal ions, melting curve data for the modified oligonucleotides and the salmon sperm DNA displayed characteristic sigmoidal behavior and transition temperatures in the range of 38.30-58.90 degrees Celsius.
Theoretical models predict that the diffusion of cultural traits will typically exhibit a sigmoidal ('S' shaped) pattern over time (Boyd & Richerson 1985; Cavalli-Sforza & Feldman 1981), while asocial learning has been expected to result in a linear, non-acceleratory, or at least non-sigmoidal increase in frequency (Lefebvre 1995).
As observed from Figure 4, all the 2,4-D treatments generally did not produce a healthy sigmoidal growth but rather linear and slow growth.
En nuestro caso, la funcion exponencial y tangente sigmoidal fueron implementadas usando series y funciones recursivas, ya que estas no se encontraban en la libreria matematica de CLDC 1.1 y MIDP 2.0.
1 se presentan las curvas de degradabilidad del pasto aleman en los tres tratamientos aplicados; las curvas tienen una expresion sigmoidal para T1 y T2 lo que sugiere la presencia de dos tasas de degradacion una lenta y otra rapida, es decir, que al inicio la tasa de degradacion no es favorecida por los efectos de los tratamientos, en cambio para T3 esta expresion tiende a ser exponencial sencilla, con solo una tasa de degradacion.
First, an appropriate model must demonstrate that "the estimated response function for the data is monotonic and sigmoidal in shape" (Neter et al., 1996, p.
Concentration-response curves constructed from this data revealed a sigmoidal curve that was best-fit by a one-site model, suggesting that perhaps only a single AR type was involved (see curve right).
squammosus; the extra parameter is needed to fit an asymptote to the sigmoidal function at a value less than 100% (DeMartini et al., 2002).
parabolic blowout dunes, transverse dunes, sigmoidal