THWN stands for "Thermoplastic Heat and Water Resistant Nylon." It is a type of electrical wire insulation that is designed to withstand high temperatures and moisture. This makes it suitable for use in various applications, including residential and commercial wiring, where durability and safety are essential. The THWN wire is often used in conjunction with other types of wires, such as THHN (Thermoplastic Heat Resistant Nylon) and NM cable (Non-Metallic Sheathed Cable). Its resistance to heat and water makes it ideal for environments where exposure to these elements is likely, ensuring reliable performance over time.