5-sec rule is what I meant by "in combat". That old terminology is still in my brain, since I just recently "really" learned what the 5-sec rule was. :P
I spent probably 45 minutes explaining this concept to my wife before she understood it. I finally figured it was important for her to understand when she switched from raiding on her hunter, to playing her priest full time.
Its one of the 'less' intuitive game mechanic's I've ever heard of.