I had to look up "zero-day attack", but it really meant what I thought it did, i.e. a previously unreported ("fresh") exploit (http://en.wikipedia.org/wiki/Zero

I had to look up "zero-day attack", but it really meant what I thought it did, i.e. a previously unreported ("fresh") exploit (http://en.wikipedia.org/wiki/Zero-day_attack http://en.wikipedia.org/wiki/Zero-day_attack). I don't understand this usage, which makes it sound as if zero-day attacks are a technical term, a category of attacks. Can anyone clarify?