half-mast vs semi

half-mast

noun
  • The state of being partially erect 

  • The lowered position, half the height of a mast, at which a flag is flown when mourning, especially expressing respect for the dead. 

  • The lowered position of any thing. 

semi

noun
  • A partial erection of the penis. 

  • A semifinal. 

  • A semi-detached house. 

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

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