The masculine is headmaster.
The Headmaster or sometimes just The Head, particularly if the post is held by a female.
He was called Armando Dippet, and was the headmaster before Albus Dumbledore.
Dolores Umbridge.
headmaster
A Headmaster (english)
Professor Albus Dumbledore.
They are generally called Headmistress, or sometimes Matron.
The Principal/President
Mr.Williams.
To be called to the Headmaster's office for a talking to or caning.
headmitress