Final answer:
The central or unifying message of a story is known as its theme. It is the main idea, lesson, or message that the author wants to convey to the readers.
Step-by-step explanation:
Theme
The central or unifying message of a story is known as its theme. It is the main idea, lesson, or message that the author wants to convey to the readers. The theme connects the plot points, conflicts, and characters to a major idea and usually provides a broad statement about humanity, life, or the universe.