death sentence vs lethal injection

death sentence

noun
  • A decree that someone be put to death as a punishment for a crime; a sentence of execution. 

  • Anything that spells death. 

lethal injection

noun
  • A means of execution or of euthanasia in which a person is injected with a fatal dose of drugs. 

How often have the words death sentence and lethal injection occurred in a corpus of books? (source: Google Ngram Viewer )