mail carrier vs shipper

mail carrier

noun
  • A person employed to deliver mail. 

shipper

noun
  • The person or organization that ships (sends) something. 

  • A box for shipping something fragile, such as bottled beer or wine. 

  • A person who supports a romantic or sexual relationship between fictional characters or real people. 

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