What is an extended metaphor? a metaphor that sustains

An extended metaphor, also known as a conceit or sustained metaphor, is an author's exploitation of a single metaphor or analogy at length through multiple linked tenors, vehicles, and grounds throughout a poem or story.

Extended Metaphor Definition. The term "extended metaphor" refers to a comparison between two unlike things that continues throughout a series of sentences in a paragraph, or lines in a poem. It is often comprised of more than one sentence, and sometimes consists of a full paragraph.

Metaphor that is developed over several lines of writing or through out the poem.