"Associate Professor" means "qualified to be Associate Professor." When I was an Associate Professor, I applied for jobs designated "Professor" (i. e., full professor) and got the promotion along with being hired.
But being hired as an Associate or Full usually means that the university also tenures you as part of hiring you. So you need to have a tenurable record, which involves publication (except at community colleges) and may require a certain number of years of teaching.
The Fiona
This is perfectly expressed. Usually, the point of hiring at Associate is to get a person tenurable at the time of hire.