A permanent wave is a hairstyling technique that creates curls or waves in the hair using chemical processes. This method involves applying a chemical solution to the hair, which alters its structure, allowing it to hold a new shape. The process typically includes wrapping the hair around rods and applying heat or additional chemicals to set the curls. The results of a permanent wave can last for several months, depending on hair type and care. While the term "permanent" suggests long-lasting effects, the curls will gradually loosen over time as the hair grows and is exposed to washing and styling.