When ordering wire what does the THHN mean?

THHN stands for Thermoplastic High Heat-resistant Nylon-coated wire. It is a type of electrical wire that is commonly used for building and construction applications due to its Excellent heat resistance, making it suitable for high-temperature environments. The nylon coating also provides added protection against moisture, abrasion, and chemicals, enhancing the wire's durability. THHN wire is typically used for both residential and commercial wiring projects.