freighter vs semi

freighter

noun
  • One who loads a ship, or one who charters and loads a ship. 

  • One employed in receiving and forwarding freight. 

  • An aircraft used mainly to carry freight; a cargo aircraft or cargo plane. 

  • A vessel used mainly to carry freight; a cargo ship. 

  • One for whom freight is transported. 

semi

noun
  • A semi-trailer; a tractor-trailer; an eighteen-wheeler; an artic. 

  • A semifinal. 

  • A semi-detached house. 

  • A partial erection of the penis. 

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