The term has long watered-down to mean any vulnerability (since it was always a zero-day at some point before the patch release, I guess is those people's logic? idk). Fear inflation and shoehorning seems to happen to any type of scary/scarier/scariest attack term. Might be easiest not to put too much thought into media headlines containing 0day, hacker, crypto, AI, etc. Recently saw non-R RCEs and supply chain attacks not being about anyone's supply chain copied happily onto HN
Edit: fwiw, I'm not the downvoter
In a security context, it has come to mean days since a mitigation was released. Prior to disclosure or mitigation, all vulnerabilities are "0-day", which may be for weeks, months, or years.
It's not really an inflation of the term, just a shifting of context. "Days since software was released" -> "Days since a mitigation for a given vulnerability was released".
This seems logical since by etymology of zeroday it should apply to the release (=disclosure) of a vuln.