Home › Words › S › sigmoidinsigmoidinsigmoidin · noun — any of a class of flavanones found in Erythrina sigmoidea.Definition from Wiktionary (CC BY-SA 3.0).Among words judged in Lexicurio's Arena, sigmoidin ranks #42,929 of 43,221 for Qualifying.EtymologyFrom translingual sigmoidea + -in.nounAny of a class of flavanones found in Erythrina sigmoidea.Definitions & examples from Wiktionary (CC BY-SA 3.0).