What term describes an image or metaphor that runs throughout and determines the form of a literary work?

The term "controlling image" refers to a recurring image or metaphor that plays a significant role in shaping the overall meaning and structure of a literary work. This image is not only present throughout the piece but also influences the reader's understanding of the themes, characters, and the narrative itself. A controlling image creates a cohesive thread that ties together the various elements of the work, adding depth and richness to the reader's experience.

In contrast, a motif is also a recurring element, but it may not have the same overpowering influence on the work as a controlling image does; motifs often support the narrative rather than define it. Theme pertains to the central idea or message conveyed in the work but does not specifically describe an image or metaphor. Symbolism involves the use of symbols to represent ideas or concepts; while it can be powerful, it doesn't specifically indicate a dominant image that shapes the form of the literary piece. Thus, "controlling image" effectively captures the essence of an image that is crucial to the structure and meaning of the entire literary work.