A glossary is a list of specialized terms with definitions. Glossaries are commonly found at the backs of books or in software manuals, to help readers and users understand terms which may be unfamiliar. A glossary could be said to act like a dictionary, except that instead of being as complete as possible, a glossary usually focuses on terms which the reader probably does not know.

The word is derived from the Latin glossa, which means “foreign word.” The first English use of the word was recorded in 1380. To contrast a glossary with a dictionary, it may help to look at the Latin roots of “dictionary,” as well. Dictio means “word,” and in Middle Latin, a dictionarium was a collection of words and phrases. Early English dictionaries focused on translation from one language into another, although in Asia, dictionaries were collections of native words with meanings and alternate spellings.

Students often use glossaries as study tools, because they quickly cover a wide range of concepts with clear, concise definitions. In a textbook with a glossary which accompanies each chapter, it can help to read the glossary first to get a basic review of the concepts which will be covered, and then to read the chapter with the glossary fresh in the mind. A glossary can also be used as a building block for flashcards, as it highlights concepts which may turn up on a final.

A glossary can also be a useful tool for someone exploring something new, whether it be computers or economics. For example, someone who is not very familiar with the Internet could benefit from reading a glossary which covers basic terms and issues. Glossaries are also an important part of software manuals, as they provide clear, in-context definitions for the material which is being covered. Since words sometimes have multiple meanings in the English language, such a glossary can be extremely useful because it will eliminate confusion.

In books which use words and terms in foreign languages, a separate foreign language glossary may be included so that the reader can quickly look up definitions. Books with a lot of technical material like publications in the sciences may also include a glossary, and some glossaries may be quite technical themselves, since they are aimed at advanced users. Most typically, a glossary is arranged in alphabetical order, which makes it easy to use.