omission vs short form

omission

noun
  • The shortening of a word or phrase, using an apostrophe ( ' ) to replace the missing letters, often used to approximate the sound of speech or a specific dialect. 

  • Something not done or neglected. 

  • An instance of those acts, or the thing left out thereby; something deleted or left out. 

  • The act of neglecting to perform an action one has an obligation to do. 

  • The act of omitting. 

short form

noun
  • A word with the same meaning as another formed by removing one or more of the syllables of the longer word, and considered a word in its own right rather than an abbreviation. 

  • Particularly in Slavic languages, a shortened form of the adjective, used predicatively. 

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