What does epoxy mean?
Epoxy refers to a class of synthetic thermosetting polymers created when an epoxide resin reacts with a curing agent, typically a hardener or catalyst. Renowned for exceptional bonding strength, chemical resistance, and durability, epoxies are widely used as adhesives, protective coatings, laminates, and structural composites across industries ranging from aerospace to home repair. In everyday usage, 'epoxy' most often denotes the familiar two-tube adhesive sold in hardware stores, which must be mixed just before application because it cures through a chemical reaction rather than simple evaporation. The word also functions as a verb meaning to bond or coat with this resin, as in 'they epoxied the seams.' Derived ultimately from Greek roots relating to oxygen, the term entered scientific vocabulary in the twentieth century as polymer chemistry advanced.
A synthetic thermosetting resin used in strong adhesives, durable coatings, and composite materials.
"Mix the epoxy thoroughly before applying it to the cracked pipe."
Often preceded by modifiers such as 'two-part' or 'five-minute' indicating how it cures.
To join, seal, or coat something using epoxy resin.
"They epoxied the carbon-fiber panels onto the frame."
Inflected forms include epoxies, epoxied, epoxying.
Used when referring to multiple types or formulations of epoxy resin; often uncountable when speaking of the substance generally.
"Marine-grade epoxies are formulated to resist saltwater corrosion."
The name 'epoxy' literally borrows from Greek for 'sharp' — because its molecules contain a strained, reactive three-membered ring chemists describe as an 'oxide' bridge.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of epoxy
Epoxy derives from the Greek prefix 'epi-' (upon) combined with 'oxy-', referring to oxygen, reflecting the presence of an epoxide (oxygen-containing three-membered ring) in its molecular structure. The term emerged in early twentieth-century chemistry as polymer scientists identified these reactive compounds. It shares its root with related chemical terms such as 'oxide' and 'oxygen,' both ultimately tracing back to the same Greek element.
Related word forms
How epoxy is actually used
Commonly used as both a countable and uncountable noun. The verb form is standard in technical and DIY contexts but less common in formal writing, where 'bonded with epoxy' is often preferred.
Easily confused with epoxy
Epidermis is the outer layer of skin, while epoxy is a synthetic adhesive resin — the words share only a superficial resemblance in spelling.