Plain English Meaning
A type of liquid plastic that hardens after a chemical hardener is added. Mixed with fiberglass cloth, it sets into a tough, lightweight shell.
Full Definition
A liquid thermosetting plastic resin that, when mixed with a catalyst (hardener), cures into a rigid solid. In aircraft work it is most commonly used with fiberglass cloth to form reinforced composite parts such as fairings, radomes, and non-structural panels.
Context Anchor
Seen in aircraft composite-material repair, fiberglass parts, fairings, panels, and maintenance material instructions.
Derivation
From Latin 'poly' (many) and 'ester' (a formed from an and an ). 'Resin' originally meant the sticky sap from trees. Together: a synthetic 'sap' built from many ester chemical links — useful because it pours like a liquid, then locks into a solid.