Usage Note: Allude and allusion are often used where the more general terms refer and reference would be preferable. Allude and allusion normally apply to indirect references in which the source is not specifically identified: Well, well always have Paris, he told the travel agent, in an allusion to Casablanca. Refer and reference, unless qualified, usually imply specific mention of a source: I will refer to Hamlet for my conclusion: As Polonius says, Though this be madness, yet there is method int. See Usage Note at refer.