Drupal 7 introduces a number of new apis and with those comes new jargon. Untangling that could be daunting. I'll try to briefly sketch what is what and relate it to terminology outside of the Drupal world.
This post is a work in progress, I am regularly revising the text from feedback.
Note Revised paragraph order and wording, clarified wording of definitions, added references, corrected glitches
