Resinous substances are organic compounds that are composed of a combination of hydrocarbons and other elements. The term 'resinous substances' is often used to refer to the lacquer-like substances produced by certain plants and trees, such as pine and fir. LACS is an acronym for 'lignin-acrylic copolymer solution, ' which is a type of resin used in the production of paints, coatings, and adhesives.