I hate the usage of the word Gish. Somehow in the past decade Gish has become an acceptable in some of RPG land as a generic term for Fighter/Magic-User. How the heck did that happen?
Gish, is title for a specific type of Githyanki as presented in the original Fiend Folio. For the vast majority of D&D campaigns, there is no reason for this word to have leaked out into general use. I've probably used Githyanki a dozen or so times in the past few decades but they've never stopped to discuss how their forces are designated or identified and the PCs (and players) never bothered to ask.
How did this decidedly uncommon encounter type enter the lamestream of D&D fandom as a common term to define character types? And why?
Nothing screams heroic archetype like a fictional word for a subset of a rarely encountered monster from within a society decidedly separate from the traditional D&D societies...