middle school: 1) a school in Britain for children between the ages of 8 and 12; 2) a school in the US for children between the ages of 11 and 14. high school: 1) a school in the US and Canada for children of 14 or 15 to 18 years old; 2) used in the names of some schools in British form children from 11 to 18 years old.

