blackboard vs seminary

blackboard

noun
  • A large flat surface, finished with black slate or a similar material, that can be written upon with chalk and subsequently erased; a chalkboard. 

verb
  • To use a blackboard to assist in an informal discussion. 

seminary

adj
  • Of or relating to seed; seminal. 

noun
  • A piece of ground where seed is sown for producing plants for transplantation. 

  • The place or original stock from which anything is brought or produced. 

  • A class of religious education for youths ages 14–18 that accompanies normal secular education. 

  • A theological school for the training of rabbis, priests, or ministers. 

  • A private residential school for girls. 

  • A Roman Catholic priest educated in a foreign seminary; a seminarist. 

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