Headmaster vs Principal

Some examples from the web:

• Headmaster leaned in and whispered something to him.
• The new members and the Headmaster must stay.
• Headmaster, we could do better.
• May I crave a glass of wine, Headmaster?
• Some student attacked Hahn and he made sure the Headmaster expelled him.
• Mr. Pak, the Headmaster is looking for you.
• In other words, she is the Headmaster's younger sister.
• You said that the Headmaster violated you.
• She said that she was violated by the Headmaster.
• Look, somehow Headmaster knew Gabe was hiding that Chemica Desin.
• Obviously this isn't what you think either, Headmaster.
• I'm sure Headmaster will have something unpleasant to say about all this.
• The Headmaster kept telling me that I must stop you.
• The Headmaster, he covered it up.
• Headmaster told us we should use it for an art project.
• Ian, for all we know, Redfang told Headmaster.
• Maybe one of us told Headmaster.
• The Headmaster 40 years ago was careful.
• That Headmaster nearly destroyed the very purpose of this school.
• Given the recent developments outside these walls, Headmaster, my father insists.

Some examples from the web:

• Venzago's current contract as Principal Conductor is through 2013.
• The easy-to-read Principal Graph shows you your growing savings balances.
• Principal partner, Simonson, Borden and Santini.
• Actually, Buffy's investigating Principal Wood.
• Principal Snyder was always on me.
• Principal Reynolds found someone to cover detention.
• Principal Farquhar say accordion is not marching band instrument.
• My predecessor, Principal Meredith Milgram.
• Principal Snyder has hidden cameras in there.
• Principal Foster says that administrators can't date teachers.
• Frank Surrey, Military Liaison and Principal Director.
• I support everything Principal Turner is doing.
• No luck needed, Principal Carl.
• Garter Principal King of Arms carries his baton of office.
• Obviously, Principal Gates jumped to conclusions.
• New Dillon High Principal, Mrs. Tami Taylor.
• Good morning, I'm Principal Green.
• The only stuff in the system about Principal Robin Wood is super-recent.
• I don't want Mr Corrigan sending me to Principal Wood again.
• Principal Snyder, great career fair, sir.