sigmoid

Etymology

Borrowing from Ancient Greek σῑγμοειδής (sīgmoeidḗs, “of the shape of sigma”), from σῖγμᾰ (sîgma, “sigma”) + -ο- (-o-) + -ειδής (-eidḗs, “-oid, -like”); Equivalent to sigma + -oid. Compare with French sigmoïde.

adj

1. (archaic) Semi-circular, like the uncial or lunar sigma (similar to English C).
2. Curved in two directions, like the letter "S", or the Greek ς (sigma); having a serpentine shape.
   1. (mathematics) Exhibiting logistic growth; having a graph that accelerates until it reaches a carrying capacity.
3. (anatomy) Relating to the sigmoid colon.

noun

1. (anatomy) Ellipsis of sigmoid colon.
2. (mathematics) Ellipsis of sigmoid function.
   If we had the textbook from a hundred years in the future that contains all the simple ideas that actually work, that take so long to identify in practice — the ReLUs instead of sigmoids — for those of us who’ve been following AI for, like, more than the last couple of years and know what I’m taking about there. 2023 June 29th, “AI will kill all of us | Eliezer Yudkowsky interview” (16:12–16:28 from the start), in The David Pakman Show, spoken by Eliezer Yudkowsky, via YouTube