identifier vs nod

identifier

noun
  • Something that identifies or uniquely points to something or someone else. 

  • One who identifies as a particular type or role; one who says and believes that they are a certain thing. 

  • A formal name used in source code to refer to a variable, function, procedure, package, etc. or in an operating system to refer to a process, user, group, etc. 

  • A primary key. 

  • Someone who identifies; a person who establishes the identity of someone or something. 

  • A guidebook that helps determine the specific class of an object (such as a mushroom, herb, fish, bird, drug, or mineral), or its individual identity (such as that of a star). 

  • A code that distinguishes a particular element from all other elements in a document. 

nod

noun
  • A reference or allusion to something. 

  • A nomination. 

  • An instance of inclining the head up and down, as to indicate agreement, or as a cursory greeting. 

  • Approval. 

verb
  • To signify by a nod. 

  • To incline the head up and down, as to indicate agreement. 

  • To allude to something. 

  • To sway, move up and down. 

  • To make a mistake by being temporarily inattentive or tired 

  • To briefly incline the head downwards as a cursory greeting. 

  • To fall asleep while under the influence of opiates. 

  • To gradually fall asleep. 

  • To head; to strike the ball with one's head. 

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