Origin: Greek prefix poly-
Polyurethane has 2 different meanings across 1 category:
any of various polymers containing the urethane radical; a wide variety of synthetic forms are made and used as adhesives or plastics or paints or rubber
"The furniture store applied a durable polyurethane finish to protect the new sofa from spills and scratches."
Any of various polymeric resins containing urethane links; used in very many industrial and domestic applications.
"The furniture repairman recommended coating the broken chair leg with polyurethane to create a durable, waterproof finish that would withstand daily use."