expression vs vocative

expression

noun
  • A colloquialism or idiom. 

  • A specific blend of whisky. 

  • The action of expressing thoughts, ideas, feelings, etc. 

  • An arrangement of symbols denoting values, operations performed on them, and grouping symbols. 

  • The process of translating a gene into a protein. 

  • A facial appearance usually associated with an emotion. 

  • (manufacturing) The act of pressing or squeezing out. 

  • A particular way of phrasing an idea. 

  • A piece of code in a high-level language that returns a value. 

  • The tone of voice or sound in music. 

  • emotional involvement or engagement in a text read aloud rendered by the voice of the reciter or the reader 

vocative

noun
  • A word in the vocative case 

  • The vocative case 

  • Something said to (or as though to) a particular person or thing; an entreaty, an invocation. 

adj
  • Of or pertaining to calling; used in calling or vocation. 

  • Used in address; appellative (said of that case or form of the noun, pronoun, or adjective, in which a person or thing is addressed). For example "Domine, O Lord" 

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