identifier vs identity

identifier

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

  • 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. 

  • 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). 

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

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

identity

noun
  • A name or persona—a mask or appearance one presents to the world—by which one is known. 

  • An element of an algebraic structure which, when applied to another element under an operation in that structure, yields this second element. 

  • A well-known or famous person. 

  • The difference or character that marks off an individual or collective from the rest of the same kind; selfhood; the sense of who something or someone or oneself is, or the recurring characteristics that enable the recognition of such an individual or group by others or themself. 

  • An equation which always holds true regardless of the choice of input variables. 

  • Sameness, identicalness; the quality or fact of (several specified things) being the same. 

  • Any function which maps all elements of its domain to themselves. 

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