Original: It was popular throughout the 1980s and the beginning of the 1990s, combining the flamboyant look of glam rock and playing a power-chord based heavy metal musical style.
Simplified: Glam metal (also known as hair metal) is a term used to describe the visual style or fashion of certain heavy metal music bands that arose in the late 1970s and early 1980s in the United States, particularly on the Los Angeles Sunset Strip music scene.