Intertextuality is the way a poem connects to other texts, especially earlier poems, through allusion, quotation, echo, parody, revision, or borrowed ideas and forms. A poem may invite readers to hear another work behind it, or it may deliberately answer, reshape, or challenge an earlier voice. The term highlights that poems often gain meaning through their relationships to other poems and cultural texts.
Example
She wrote the same opening line as the old ballad, then turned it aside:
The night was dark, but I kept walking on
past the gate, past the fields, past the fear
that had lived there for years.
The borrowed line makes readers hear the ballad, while the new lines change its meaning.