There are two definitions of aporia included in the Oxford English Dictionary: the adjective, “aporetic” defined as “to be at a loss,” “impassable,” and “inclined to doubt, or to raise objections”; and the noun “aporia,”defined as the “state of the aporetic” and “a perplexity or difficulty.” The two early textual uses refer to aporia's rhetorical application.

Aporia, in its rhetorical usage, is a feigned expression of doubt which is often followed by the expression of a conclusive thought. This conclusive thought, as often used in Plato's early dialogues. In its modern usage, primarily used by post-structuralists, aporia has addressed its philosophical application. It is defined more as a specific moment in philosophical thought, rather than a rhetorical expression, where in thought an individual reaches an impasse, or a point of doubt and indecision. Jacques Derrida has used the term to “indicate a point of undecidability, which locates the site at which the text most obviously undermines its own rhetorical structure, dismantles, or or deconstructs itself.”