What does "IP" mean in military aviation?

In Catch-22 I found the mention of the abbreviation "IP":

One of the surprising things always was the sense of calm and utter silence, broken only by the test rounds fired from the machine guns, by an occasional toneless, terse remark over the intercom, and, at last, by the sobering pronouncement of the bombardier in each plane that they were fully at the IP and about to turn toward the target.

What does IP mean?

In Wikipedia I could not find anything that would make sense in the context

Solution 1:

According to this list of Military Aviation terms:

IP - Initial Point - the last navigation way point for a strike aircraft before beginning a bomb run. Usually the weapons officer has control of the aircraft from the I.P. to the target

Which does seem to match up to the context of the quote in the question.