variant vs variation

variant

noun
  • A different sequence of a gene (locus). 

  • Something that is slightly different from a type or norm. 

  • A variable that can hold any of various unrelated data types. 

  • One of a set of words or other linguistic forms that conveys the same meaning or serves the same function. 

adj
  • Showing deviation or disagreement. 

  • Showing variety, diverse. 

  • Covariant and/or contravariant. 

variation

noun
  • The modification of a hereditary trait. 

  • Deviation from the mean orbit of a heavenly body. 

  • The act of varying; a partial change in the form, position, state, or qualities of a thing. 

  • The angular difference at the vessel between the direction of true north and magnetic north. 

  • A related but distinct thing. 

  • A line of play that differs from the original. 

  • A technique where material is repeated with alterations to the melody, harmony, rhythm, timbre, texture, counterpoint or orchestration; but with some invariant characteristic, e.g. a ground bass. 

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