Home › Words › G › gelcoatgelcoatgelcoat · noun — A material used to provide a high-quality finish on the visible surface of a fibre-reinforced composite, and often taking the form of a thermosetting polymer based on epoxy or unsaturated polyester resin chemistry.Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom gel + coat.nounA material used to provide a high-quality finish on the visible surface of a fibre-reinforced composite, and often taking the form of a thermosetting polymer based on epoxy or unsaturated polyester resin chemistry.Definitions & examples from Wiktionary (CC BY-SA 3.0).