校长(xiào zhǎng) - headteacher in Mandarin

校长 (xiàozhǎng) is the headteacher, the person in charge of a school. 校 (xiào) means "school", the same character in 学校 (xuéxiào), and 长 (zhǎng) means "head" or "chief", the character that also gives 家长 (jiāzhǎng), "parent, head of the family", and 市长 (shìzhǎng), "mayor".

Note the tone on 长: as "head, chief, elder" it is pronounced zhǎng, third tone, quite different from cháng, second tone, meaning "long", in words like 长城 (Chángchéng), the Great Wall. Mixing the two readings up is one of the more common beginner slips.

校长 (xiàozhǎng) is used for the head of a primary or secondary school, and for a university's equivalent too in mainland usage, though British learners more often meet the word first in the school context, describing the person who runs assemblies and signs off school trips.