What literary device uses a part of something to signify the whole?

The literary device that uses a part of something to signify the whole is known as synecdoche. This figure of speech allows writers to create vivid imagery and convey meanings more effectively by referring to a larger concept through a specific part. For example, saying "the sails" to refer to a ship indicates the vessel as a whole, not just its sails. This technique helps deepen the reader's understanding and connection to the subject.

In contrast, alliteration focuses on the repetition of consonant sounds at the beginning of words in a phrase, enhancing the musical quality of language rather than creating relationships of part to whole. Metonymy involves using a related term or concept to represent something rather than directly using a part, such as referring to "the crown" as a representation of monarchy, but does not specifically use a physical part. Hyperbole is an exaggerated statement not meant to be taken literally, often used for dramatic effect, and thus does not qualify as it does not specifically involve part-whole relationships.