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Assistant Principal from WikiPedia:

Principal or Head of School is the title of the head administrator of an elementary school, middle school, or high school in some English-speaking countries, including the United States, India and Australia. Public schools in the United States generally use the title Principal whereas private schools in the United States generally use the title Head of School. In other English-speaking countries, the terms head teacher, head master or head mistress are used. Books and documents relating to the early days of public education in the United States show that the title was originally Principal Teacher.

In 1999, there were about 129,000 "principals" in the United States.

In many Australian schools, a principal is the head administrator of a school who has been appointed to her/his position by the school board, superintendent, or other body.

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