So if you're late, you have to go to the head master.
所以如果你迟到了，你必须去找校长。
2005 ESLPod
In school, the " principal" is the director or head master or leader of the school.
在学校，“校长”是学校的主任或校长或领导。
英语百科
Head teacher 校长
（重定向自Head master）
A head teacher (also known as school principal, headteacher, headmaster, headmistress or the head), is the teacher with the greatest responsibility for the management of a school.