Allusion is a literary device that references a person, place, event, or work of art, often without explicit identification. It relies on the reader's familiarity with the referenced subject to create deeper meaning or context. For example, mentioning Romeo and Juliet in a story about star-crossed lovers evokes themes of love and tragedy without needing detailed explanation. Writers use allusion to enrich their narratives and connect with readers on a cultural or emotional level. By invoking well-known figures or events, such as the Trojan War or Shakespeare, authors can convey complex ideas succinctly, enhancing the reader's experience and understanding.