What does the term 'glossary' refer to in a book?

The term 'glossary' specifically refers to a list of difficult or specialized words along with their meanings, typically found at the end of a book. This section is particularly valuable for readers who may encounter unfamiliar terms, as it provides definitions and clarifies usage within the context of the text. It serves as a helpful resource to enhance the reader's understanding of the material, making it easier to grasp concepts that might be new or complex.

The other options do not accurately define a glossary. A concise summary of the book's themes would be considered a synopsis, while author background information pertains to an "about the author" section. A catalog of illustrations and images would be more like a list of figures or a visual index rather than a glossary. Hence, recognizing that a glossary focuses on word meanings is essential for understanding its role in supporting reader comprehension.