A "hot perm" is a hair treatment that uses heat to create curls or waves in the hair. This process involves wrapping sections of hair around rods and applying a chemical solution, followed by heat from a machine or heated rods. The heat helps the chemicals penetrate the hair shaft, resulting in long-lasting curls. Hot perms are often preferred for their ability to produce more defined and bouncy curls compared to traditional cold perms. The results can last for several months, making it a popular choice for those looking to change their hairstyle without daily styling efforts.