ancestor vs lexical item

ancestor

noun
  • A word or phrase which serves as the origin of a term in another language. 

  • One who had the same role or function in former times. 

  • One from whom an estate has descended;—the correlative of heir. 

  • One from whom a person is descended, whether on the father's or mother's side, at any distance of time; a progenitor; a forefather. 

  • An earlier type; a progenitor 

verb
  • To be an ancestor of. 

lexical item

noun
  • A term—word or a sequence of words—that acts as a unit of meaning, including words, phrases, phrasal verbs and proverbs, exemplified by cat, traffic light, take care of, by-the-way, and don't count your chickens before they hatch. 

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