This is a revival of my original proposal posted back in December 2015, now with new sources to support it.
Currently on this wiki, the terms Land, World and Realm are used interchangeably and with no real consistency to distinguish the differences between the terms. Realm is also used on this wiki to denote a region of Fairy Tale Land. I propose a realignment of these terms for consistency with what is presented on-screen and by statements from interviews with the writers.
Realm: This is the collective terminology for Lands and Worlds. Realm has been used interchangeably on-screen with Land and World, mainly in speech. Wish Realm (a land) and Dark Realm (unknown) are also used by this wiki to denote two realms that do not yet have on-screen names.
Land: These are the traditional realms such as FTL, LWM, Wonderland, etc. They can be travelled to with the use of standard portals such as Magic Beans and Rabbit Holes. Lands are culturally and ethnically diverse, with kingdoms and countries to divide them. Lands can typically be distinguished by their names: Fairy Tale Land, Wonderland, Land Without Magic, etc.
World: These realms are distinct from lands in that they exist for specific purposes and are not normal realms that people can live and develop in, i.e. Netherworld is between life and death, Underworld is limbo for the dead, etc. Conventional portals do not work for these realms, more complex methods are generally required. Worlds also typically have world in their names.