noun. ['ˌpɑːˌliːˈʊrəˌθeɪn'] 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.
1. Noun, singular or mass Apply a coat of polyurethane to your door to help protect it against the elements. 2. Verb, base form You'll thank me ... unless you're allergic to polyurethane."