High fantasy, or epic fantasy, is a subgenre of fantasy[1] defined by the epic nature of its setting or by the epic stature of its characters, themes, or plot.[2] High fantasy is usually set in an alternative, fictional ("secondary") world, rather than the "real" or "primary" world.[2] This secondary world is usually internally consistent, but its rules differ from those of the primary world. By contrast, low fantasy is characterized by being set on Earth, the primary or real world, or a rational and familiar fictional world with the inclusion of magical elements.[3][4][5][6]
^"Defining the Genre: High Fantasy". fandomania. 11 May 2011. Archived from the original on 22 March 2019. Retrieved 8 August 2016. High Fantasy is probably one of the most recognizable subgenres of Fantasy.
^C.W. Sullivan has a slightly more complex definition in "High Fantasy", chapter 24 of the International Companion Encyclopedia of Children's Literature by Peter Hunt and Sheila G. Bannister Ray (Routledge, 1996 and 2004), chapter 24.