The origins of estoppel

From Wikipedia (link):

Estoppel is a legal doctrine recognized both at common law and in equity in various forms. It is meant to complement the requirement of consideration in contract law. In general it protects a party who would suffer detriment if:

  • The defendant has done or said something to induce an expectation
  • The plaintiff relied (reasonably) on the expectation…
  • …and would suffer detriment if that expectation were false.

From ‘Lectric Law Library (link):

An example of the slowly disappearing tendency of the legal profession to speak in secret code. All it means is ’stopped,’ ‘blocked’ or ‘not allowed.’ Not only is it bizarre but the term does not appear to originate in any known language. Our research indicates it started either as a legal fraternity’s drunken prank or was the result of an unknown Judge’s severe speech impediment.