I recently found out that “extrovert” is a misspelling and that it’s actually written extravert. That makes sense, because other words use the same prefix, e.g. extraordinary, extradite, etc., but nothing I can think of begins with extro-(1).
However, intro- and intra- seem to be two different prefixes. There is introduce and introspect on the one hand, and intravenous and the more recent neologism intranet on the other hand.
What is the difference between intro- and intra- and what are their origins?
((1) Even the end-credit section of a movie, the opposite of the intro, isn’t called an extro :) )