Intertextuality is the shaping of a text's meaning by another text, either through deliberate compositional strategies such as quotation, allusion, calque, plagiarism, translation, pastiche or parody, or by interconnections between similar or related works perceived by an audience or reader of the text. These references are sometimes made deliberately and depend on a reader's prior knowledge and understanding of the referent, but the effect of intertextuality is not always intentional and is sometimes inadvertent. Often associated with strategies employed by writers working in imaginative registers (fiction, poetry, and drama and even non-written texts like performance art and digital media), intertextuality may now be understood as intrinsic to any text.

Intertextuality has been differentiated into referential and typological categories. Referential intertextuality refers to the use of fragments in texts and the typological intertextuality refers to the use of pattern and structure in typical texts. A distinction can also be made between iterability and presupposition. Iterability makes reference to the "repeatability" of certain text that is composed of "traces", pieces of other texts that help constitute its meaning. Presupposition makes a reference to assumptions a text makes about its readers and its context. As philosopher William Irwin wrote, the term "has come to have almost as many meanings as users, from those faithful to Julia Kristeva's original vision to those who simply use it as a stylish way of talking about allusion and influence".