Am I missing where they indicate what they mean by "active learning"? All I see are references to clickers and asking individual students questions during a lec

Am I missing where they indicate what they mean by "active learning"? All I see are references to clickers and asking individual students questions during a lecture. Sounds like it's actually just a question of dull lecturing vs engaging lecturing to me. Can anyone provide a summary of what "active learning" means in this context?