janitor vs porter's lodge

janitor

noun
  • A caretaker or custodian; someone who maintains a school building specifically and may serve other administrative roles. 

  • Someone who looks after the maintenance and cleaning of a public building. 

  • A doorman. 

  • A moderator for a discussion forum. 

porter's lodge

noun
  • A building for the porter(s) near the gate of a castle, college, etc., (historical) formerly used as a place of punishment for the staff. 

  • An equivalent room near the gate of a college, chiefly used as a mailroom. 

How often have the words janitor and porter's lodge occurred in a corpus of books? (source: Google Ngram Viewer )