a sticky organic substance secreted by some trees, typically flammable in nature, insoluble in water, and used to make plastics, varnishes, and some inks;
e.g. The wood was coated with resin so that it didn't get damaged by moisture.
(noun)
a sticky synthetic substance that is similar to the organic resin secreted by trees, mainly used to make varnishes, plastics, and adhesives;
e.g. A charm made of shiny resin hung from a chain around her neck.
(verb)
to treat something by rubbing or coating it with resin;
e.g. He will resin the furniture to make it stronger and give it a shiny finish.