educational institution vs junior high school

educational institution

noun
  • A place where people of different ages gain an education, including preschools, childcare, elementary schools, and universities. 

junior high school

noun
  • A school for children who have completed elementary school or grade school, but are not yet old enough for high school. In the US, it often includes grades 7 and 8, and possibly also 6 or 9. 

How often have the words educational institution and junior high school occurred in a corpus of books? (source: Google Ngram Viewer )