from The American Heritage® Dictionary of the English Language, 4th Edition
- pro. Chiefly Southern U.S. Whichever. See Regional Note at everwhere.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adv. whichever
Sorry, no etymologies found.
To aid the professor's search for similar examples, I offer these: everwhich, everhow, everwhen, and howsomeever.
The well-known tendency in the South to drop the y in every (as in everday), allows the conjunction everwhich.