merchant marine vs vessel

merchant marine

noun
  • A ship dedicated to commercial, rather than military, purposes. 

  • Synonym of merchant navy. The fleet considered as an entire combined force. 

vessel

noun
  • Any craft designed for transportation on water, such as a ship or boat. 

  • A craft designed for transportation through air or space. 

  • A container of liquid or other substance, such as a glass, goblet, cup, bottle, bowl, or pitcher. 

  • A tube or canal that carries fluid in an animal or plant. 

  • A person as a container of qualities or feelings. 

verb
  • To put into a vessel. 

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