SIGMOID is a playable word

sigmoid Scrabble® Dictionary

noun
pl. sigmoids
an S-shaped curve in a bodily part
62 Playable Words can be made from "SIGMOID"
   2-Letter Words (13 found)
   3-Letter Words (25 found)
   4-Letter Words (15 found)
   5-Letter Words (6 found)
   6-Letter Words (2 found)
   7-Letter Words (1 found)