alma mater vs middle school

alma mater

noun
  • A school, college or university from which an individual has graduated or which he or she has attended. 

  • A school's anthem or song. 

middle school

noun
  • An educational level or stage between primary school and secondary school. 

  • A school which crosses the traditional divide between primary school and secondary school. 

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