There are **research** universities and there are **teaching** universities. 

 - Research universities have graduate programs and their focus is on doing research. This means most professors teach one or two classes (some have 0!) but have other obligations.

 - Teaching universities on the other hand don't typically have graduate programs (if they do, it is just a Master's program) and the professors have full teaching loads (I think 3-4 courses is the norm) with little expectations to publish. 
  - For example, Austin Peay State University, where I did my undergrad is considered a teaching university. Every professor has a full course load and not a single one of the professors I had has published in the past 5 years.

**UPDATE:** chronicle.com defines **teaching university** as one where professors have "a standard teaching load of four courses a semester", from [Interviewing at a Teaching University][1].


  [1]: http://chronicle.com/article/Interviewing-at-a-Teaching-/45217/