grammar school vs senior high school

grammar school

noun
  • A secondary school that stresses academic over practical or vocational education, until recent times open to those pupils who had passed the 11-plus examination. 

  • Elementary school. 

senior high school

noun
  • An institution which provides secondary education, typically in grades 10, 11, and 12, and often also in grade 9. 

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