Longman Dictionary of Contemporary English
head teacher
noun
EXAMPLES FROM CORPUS
▪ First the head teacher asks the girl to put her allegations in writing.
▪ In the evening I consulted a friend who is also a local head teacher.
▪ The head teacher has the reputation of the school to protect, and might not want to lose an otherwise good teacher.
▪ The man with whom he joined to start the program is head teacher.
Wiktionary
head teacher
n. 1 (context education English) A gender-neutral term for a headmaster or headmistress. 2 (alternative form of headteacher English)
WordNet
head teacher
n. the educator who has executive authority for a school; "she sent unruly pupils to see the principal" [syn: principal, school principal, head]
Wikipedia
Head teacher
A HEADMASTER (also known as HEADMASTER''', headmaster, headmistress or the head), is the teacher with the greatest responsibility for the management of a school.