A glossary is a list of specialized words or terms with their definitions, usually found at the back of a textbook or technical book. Think of it as a mini-dictionary created specifically for that book, explaining words the author thinks readers might not know.

If you're reading a science textbook about cells, the glossary might define terms like mitochondria, chloroplast, and nucleus. In a history book about ancient Rome, you might find words like aqueduct, forum, and patrician. The glossary saves you from having to look up unfamiliar words in a regular dictionary because it gathers all the important terms in one convenient place.

Glossaries are particularly helpful when a subject uses words in special ways. For instance, in everyday speech, a cell might mean a prison room or a phone, but in biology, it means something completely different. The glossary tells you exactly what the word means in that particular context.

When you encounter a confusing term while reading, flipping to the glossary can quickly clear things up and keep you moving forward with your learning.