associative vs combinatorial

associative

adj
  • Pertaining to, resulting from, or characterised by association; capable of associating; tending to associate or unite. 

  • Such that, for any operands a,b and c, (a*b)*c=a*(b*c); (of a ring, etc.) whose multiplication operation is associative. 

  • Addressable by a key more complex than an integer index. 

combinatorial

adj
  • Of, pertaining to, or involving combinations. 

  • Of or pertaining to the combination and arrangement of elements in sets. 

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