Allusion

Allusion is a figure of speech, in which an object or circumstance from an unrelated context is referred to covertly or indirectly. It is left to the audience to make a direct connection. Where the connection is directly and explicitly stated (as opposed to indirectly implied) by the author, it is instead usually termed a reference. In the arts, a literary allusion puts the alluded text in a new context under which it assumes new meanings and denotations. It is not possible to predetermine the nature of all the new meanings and inter-textual patterns that an allusion will generate. Literary allusion is closely related to parody and pastiche, which are also "text-linking" literary devices.

In a wider, more informal context, an allusion is a passing or casually short statement indicating broader meaning. It is an incidental mention of something, either directly or by implication, such as "In the stock market, he met his Waterloo."