partially ordered set vs well-order

partially ordered set

noun
  • A set that has a given, elsewhere specified partial order. 

  • The ordered pair comprising a set and its partial order. 

well-order

noun
  • A total order of some set such that every nonempty subset contains a least element. 

verb
  • To impose a well-order on (a set). 

How often have the words partially ordered set and well-order occurred in a corpus of books? (source: Google Ngram Viewer )