- an organic chemical that contains a group consisting of an oxygen atom bound to two already connected atoms, usually carbon (epoxy group).Compare epoxy(def 2).
- a compound containing an oxygen atom joined to two different groups that are themselves joined to other groups
- (as modifier)epoxide resin
- A ring-shaped compound consisting of an oxygen atom bonded to two other atoms, usually of carbon, that are already bonded to each other. Epoxides are used to make epoxies.