Nightmare: A frightening or emotionally disturbing sleep experience, which can be caused by stress, anxiety, traumatic experiences, changes in metabolism, or uncomfortable sleeping positions.
Nightmare Disorder: A clinical condition in which nightmares occur frequently, causing fear of sleep, frequent awakenings, and disrupting daytime functioning. It requires medical attention if severe.
Difference from Night Terrors: Nightmares occur during REM sleep and retain dream memories, while Night Terrors occur early in sleep (non-REM) and often lack memories.
Other Uses in Popular Culture
Music: Avenged Sevenfold’s 2010 album “Nightmare,” which includes the hit song of the same name.
Video Games: The violent animatronic character named Nightmare in the Five Nights at Freddy’s game series.
Bottom Line
Generally, a nightmare refers to a frightening, nightmarish experience; but it can also refer to dark pop culture works, such as band albums or game characters.
