elementary school vs secondary school

elementary school

noun
  • A school for children, typically older than toddlers and younger than adolescents. In the U.S., elementary schools cover grades 1 through 5, and the ages of the children are usually 6-11 years. At a minimum, elementary schools will teach basic reading, writing, arithmetic, and history. Historically also used in the UK. 

secondary school

noun
  • In the UK and Ireland, a state school attended between the ages of 11 and 16 or 18. 

  • School with education level between primary school and university. 

  • The federally designated, graduation-separated classification of grades 9–12 (approximately ages 14–18), regardless of whether they are compiled together in one school or separate from the other grades. 

  • Middle school; junior high school; a school that one attends between the ages of 12-17 (equivalent of grades 7-10 in North America, and years 7-10 in Australia). 

How often have the words elementary school and secondary school occurred in a corpus of books? (source: Google Ngram Viewer )