what does " Practice Professor" mean? Is it a level of professor?

A practice professor or "Professor of the Practice" is a non-tenured person appointed to the academic staff of an American university who has exceptional experience in their "practice" (profession) and a Doctor's degree.

Note that in American universities a "professor" is practically any lecturer with a doctor's degree, whereas in much of the rest of the world, the title is reserved for senior academics. In much of the world, including most Commonwealth nations (such as the United Kingdom), German-speaking and northern Europe, "Professor" is reserved only for the most senior academics at a university, typically a department chair, or an awarded chair specifically bestowed recognizing an individual at a university. A Professor is a highly accomplished and recognized academic, and the title is awarded only after decades of scholarly work. In the United States and Canada the title of professor is granted to all scholars with Doctorate degrees (typically Ph.D.s) who teach in two- and four-year colleges and universities, and is used in the titles Assistant Professor and Associate Professor, which are not considered Professor-level positions elsewhere.

this is not the case in Canada.

It seems you've pulled this information from Wikipedia, which seems to think that the Canadian and American post-secondary systems are the same. They are not.

I did "pull" that information from Wikipedia, and perhaps I could have edited it a bit. I saw a page of guidance for new students at the Macleans website ("What do you call a professor?") that suggested that ordinary lecturers are often informally referred to as "professors" and there is a US-style academic rank of "associate professor", and (as you imply) only those who are "Professors at rank" should actually be addressed as "Professor". This is much more like the US practice than, for example, in the UK, where in a university department there will only be one professor.

The U.S. seems to have a system where universities are sometimes called colleges.

Colleges in Canada are more like technical schools, and have no professors (unless it's a former university prof who didn't make tenure and needed a teaching gig. That person might be called Dr. X, but won't be referred to as being a professor).

Most college programs are three years in length, though there is a range of 1 - 4 years. Universities in Canada have entirely dropped the general three year option and now only offer four year honours programs at the undergraduate level.

The position of professor in an American university has 3 ranks: assistant, associate and full. The only ones that can legitimately call themselves "professor" are those with the title of full professor. The rank of full professor requires at least 12 years serving at the two lower ranks. To become a full professor you must undergo a review, involving in part scrutiny by a board of peers. The review takes about one year. Many never make the rank of full professor. Achieving full professor is a major career accomplishment.

Not a very accurate summation, C.

http://en.wikipedia.org/wiki/Professors_in_the_United_States

USC just appointed a 'practice professor' to Chair of their Department of Journalism--this 'practice professor' must now mean more than an education, at least to a private university like USC
No prior teaching experience, just coronation to the Chair.