Allusion is a short, informal reference to a famous person or event:
- You must borrow me Gargantua’s mouth first. ‘Tis a word too great for any mouth of this age’s size. –Shakespeare
- If you take his parking place, you can expect World War II all over again.
- Plan ahead: it wasn’t raining when Noah built the ark. –Richard Cushing
- Our examination of the relation of the historian to the facts of history finds us, therefore, in an apparently precarious situation, navigating delicately between the Scylla of an untenable theory of history as an objective compilation of facts . . . and the Charybdis of an equally untenable theory of history as the subjective product of the mind of the historian . . . . –Edward Hallett Carr
Notice in these examples that the allusions are two very well-known characters or events, not obscure ones. (The best sources for allusions are literature, history, Greek myth, and the Bible.) Note also that the reference serves to explain or clarify or enhance whatever subject is under discussion, without sidetracking the reader.
Allusion can be wonderfully attractive in your writing because it can introduce variety and energy into an otherwise limited discussion (an exciting historical adventure rises suddenly in the middle of a discussion of chemicals or some abstract argument), and it can please the reader by reminding him of a pertinent story or figure with which he is familiar, thus helping (like analogy) to explain something difficult. The instantaneous pause and reflection on the analogy refreshes and strengthens the reader’s mind.