Assuming your context shows you that they are indeed referring to the head teacher

A head teacher or school principal (also known as headteacher,[1] headmaster, headmistress or the head, sometimes informally in Scots, the heidie or heedie) is the most senior teacher, leader and manager of a school. In the past, the headmaster or headmistress of a British private school was often the owner of the school or a member of the owning family, and the position often remained in the family for many generations.
In Scotland, such officials are sometimes known as the "rector", most commonly in independent schools. In North America, Australia and Ireland (including Northern Ireland), such officials are usually known as the "school principal", but some schools, primarily independent schools, use the term "headmaster" or "head master".

http://en.wikipedia.org/wiki/Head_teacher#United_States