A school for children that have completed elementary school or grade school, but are not yet old enough for high school. In the US, it often includes grades 6 or 7 through 9
In California the term originally used was intermediate high school, later shortened to intermediate school, but the term junior high school is rapidly supplanting the others.
A school in the U.S. system generally including the seventh, eighth, and sometimes ninth grades. a school in the US and Canada for children aged between 12 and 14 or 15 middle school , senior high school