nexus vs old boy network

nexus

noun
  • A form or state of connection. 

  • A centre or focus of something. 

  • A person who had contracted a nexum or obligation of such a kind that, if they failed to pay, their creditor could compel them to work as a servant until the debt was paid; an indentured servant. 

  • The relationship between a vendor and a jurisdiction for the purpose of taxation, established for example by the vendor operating a physical store in that jurisdiction. 

  • A connected group; a network, a web. 

  • In the work of the Danish linguist Otto Jespersen (1860–1943): a group of words expressing two concepts in one unit (such as a clause or sentence). 

old boy network

noun
  • A presumed unacknowledged system of association between childhood friends (especially those at school or university together), used for mutual assistance or favouritism. 

How often have the words nexus and old boy network occurred in a corpus of books? (source: Google Ngram Viewer )