It often happens that a political or other figure makes a remark on to which the media fasten. That remark then goes on to become part of the language. Examples were Poindexter's 'plausible deniability', and Armstrong's 'economical with the truth', discussed elsewhere. I hear the latter expression used frequently as a euphemism for a lie.
Another classic example was when Mandy Rice Davies was told in court (1963) that Lord Astor denied having sex with her, she replied 'Well, he would wouldn't he?' Nowadays the expression is often used, sometimes by people who do not know its origin.
Is there a name for these coinages?