I've seen alternate used in other places to refer to candidate keys that are not currently the primary key, though I'm fairly sure it isn't a defined standard term.
Regarding the "industry term", search:
site:oracle.com "alternate key"
site:microsoft.com "alternate key"
site:ibm.com "alternate key""defined standard" !== "industry term", though I accept your point that it appears to be more common than I was thinking.
IIRC it wasn't introduced to me when learning databases academically which I was assuming to be a standards compliant environment, but that was quite some years ago so I may or may not R C...
Industry term. But it is usually unknown to people who tend to use id as primary key for every table.
Is this an industry term or are you just using it here to emphasize the difference?