counterpart vs peer

counterpart

noun
  • One who or that which has corresponding functions or characteristics. 

  • Either of two parts that fit together, or complement one another. 

  • One who or that which resembles another. 

  • A duplicate of a legal document. 

  • Either half of a flattened fossil when the rock has split along the plane of the fossil. 

verb
  • To counterbalance. 

peer

noun
  • Somebody who is, or something that is, at a level or of a value equal (to that of something else). 

  • Someone who pees, someone who urinates. 

  • A look; a glance. 

  • A noble with a title, i.e., a peerage, and in times past, with certain rights and privileges not enjoyed by commoners. 

  • Someone who is approximately the same age (as someone else). 

  • A comrade; a companion; an associate. 

verb
  • To make equal in rank. 

  • To carry communications traffic terminating on one's own network on an equivalency basis to and from another network, usually without charge or payment. Contrast with transit where one pays another network provider to carry one's traffic. 

  • To look with difficulty, or as if searching for something. 

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