partially ordered set vs relation

partially ordered set

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

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

relation

noun
  • Specifically, a set of ordered pairs; a binary relation. 

  • The manner in which two things may be associated. 

  • A set of ordered tuples. 

  • A set of ordered tuples retrievable by a relational database; a table. 

  • The act of intercourse. 

  • The act of relating a story. 

  • A member of one's extended family; a relative. 

  • A statement of equality of two products of generators, used in the presentation of a group. 

  • A subobject of a product of objects. 

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