half sister vs peer

half sister

noun
  • A female sibling sharing a single parent. 

peer

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

  • Someone who pees, someone who urinates. 

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

  • 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. 

  • 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 half sister and peer occurred in a corpus of books? (source: Google Ngram Viewer )