D) A glossary provides definitions of words in a book. A glossary is a list of terms used in a particular book or subject area and their definitions. It is usually found at the back of the book and provides readers with a quick reference to the meanings of specific words used in the text. A dictionary, on the other hand, provides definitions of words in general and is not specific to any particular book or subject area. A thesaurus provides synonyms and antonyms of words, and it is usually found alongside a dictionary.