Final answer:
The term describing the messages and purposes an author embeds in their work is 'Authorial intent'. Unlike themes or motifs, it encompasses the broader reasons and meanings the author seeks to express in the piece.
Step-by-step explanation:
When discussing literature, the term authorial intent is used to describe the purpose and meaning that the author embeds within their work. Unlike themes, which are the central and unifying concepts of a piece, or motifs, which are recurring elements that help to develop and inform the theme, authorial intent addresses the underlying reasons why an author created the piece as they did. It's not about a single message or a moral like in Aesop's Fables, but rather about the broader complexities of human existence that an author aims to convey.
The question of what the author intended is often misleading, as it implies the author failed to communicate clearly when in reality, the text itself should be the focus of our interpretation. Engaging with the text to discover themes or motifs ultimately leads to a deeper understanding of the author's intent. Notably, motifs can be particularly helpful in leading readers to discern themes by highlighting important concepts through their repetition and symbolic value.