Extended metaphor

An extended metaphor, also known as a conceit or sustained metaphor, is the use of a single metaphor or analogy at length in a work of literature. It differs from a mere metaphor in its length, and in having more than one single point of contact between the object described (the so-called tenor) and the comparison used to describe it (the vehicle). These implications are repeatedly emphasized, discovered, rediscovered, and progressed in new ways.