You can make a word become a wiki word if you take at least two words, like for example "wiki" and "word", capitalize them to become "Wiki" and "Word" and then pull them together, like: "WikiWord". Not that was easy wasn't it?
Here's a more formal definition:
A WikiWord is a word with at least two pairs consisting of:
(UPPERCASE ASCII LETTER : lowercase ascii letter, _ , "0123456789")