clerestory

The Macquarie Dictionary online gives the etymology as:
cler- clear + French estoré built

Perhaps there's some Latin in the "cler" part if one goes back far enough (clarus?).

The etymology is clearly English, although from the spelling I can imagine that is why you'd think it was Latinate. Knowing the etymology, it couldn't be cle-RES-tor-y, but I give you full credit. Just assume that your ex got lucky.

I never did the spelling bee, but this seems like it would be a great word.

Gosh, is it really pronounced like that? Your ex may have been in the right technically, but cle-RES-tor-y is still the clear moral winner.

One of those words that tends to be discovered in reading rather than in conversation. So for many years I thought it was pronounced cle-RES-tor-y (four syllables, stress on the second). Had a frustrating (’cause I lost) argument with my first boyfriend who, of course, pronounced it clear-story as it should be. But when it came to awry I won and all was well again.