Any made up word that is created for a specific use and definition.
These words unto themselves are nonsensical and nondescriptive. They are also not a language-based creation i.e. Latin roots, etc.
The word 'ogamaquin' is an ogamaquin. Words created by authors for fiction are commonly ogamaquins, such as 'muggles' or 'munchkins'. Many ogamaquins ultimately are absorbed into language and become accepted as words.