Three words security teams use precisely, and everyone else mixes up — and the mix-up is exactly why security budgets get spent in the wrong place.
"Vulnerability," "threat," and "risk" get used as near-synonyms in everyday speech — all three roughly mean "something bad about security." In security practice they mean three specific, different things, and the difference isn't academic: it's the entire logic behind why some vulnerabilities get patched tonight and others sit open for a year without anyone losing sleep over it.