Ma'anar ƙamus na "enol" wani fili ne mai ƙunshi duka ƙungiyar alkene (C=C) da ƙungiyar hydroxyl (-OH) waɗanda aka haɗa da carbon atom iri ɗaya. Enols sune masu ta atomatik na ketones ko aldehydes kuma su ne masu tsaka-tsaki masu mahimmanci a cikin haɗin kwayoyin halitta da kwayoyin halitta. Sunan "enol" ya fito daga kalmomin "ene" (yana nufin ƙungiyar alkene) da "giya" (yana nufin rukunin hydroxyl).