The thesaurus (thi-SOR-us) is one of the oldest and most widely used reference books, next to the dictionary. A thesaurus is a collection of phrases, concepts, and related words usually alphabetized like a simple dictionary. The first English language thesaurus, Roget’s Thesaurus, was created in 1852 by Dr. Peter Mark Roget (1779-1869). The term “thesaurus” comes from the Greek word “thesauros,” meaning “treasure.” Roget created a reference book that is the opposite of a dictionary. A dictionary is the book to use when you know a word and want to spell it correctly or learn more about it. When you know what a certain word means, but you’re looking for a different word to convey that same meaning, a thesaurus is the book you need.

A thesaurus contains words (labeled with their part of speech) and their synonyms (words that mean the same) and sometimes their antonyms (words that mean the opposite). Some thesauruses include popular phrases/ideas like “what-do-you-call-it” and “as pretty as a picture.” A thesaurus does not include lengthy definitions of words like you find in a dictionary. A thesaurus requires you to know the intended meaning of a word in its context in order to find its best synonym(s). Language reference books, like a thesaurus, help us find alternative words and/or phrases to convey a particular idea or concept.

A thesaurus groups words of very similar meaning and orders them in a hierarchy of the most closely related word to a word that may have only a shade of the entry word’s meaning. For example, when looking for the word beautiful, the synonyms listed in one particular thesaurus are: attractive, beauteous, bonny, comely, dishy, fair, foxy, good-looking, handsome, lovely, pretty, stunning, and well-favored. When using beautiful in the context of something/someone being pretty, “attractive” appears first as the most closely related synonym with “well-favored” coming last and having only a shade of the meaning beautiful.

Thesauruses come in many forms—a paper-filled book, a word processing tool on your computer, a hand-held electronic device, or on a Web site. Thesauruses may differ slightly in the way to search for words and their synonyms. Instead of finding entry words alphabetically, the user may have to search entry words in an index found at the back of the book and refer to a page number where an entire category of similar words will be listed. For younger students, the alphabetical entry listing is the best introduction to the thesaurus since it follows the same layout as a regular dictionary.

In the current technological world, students will likely learn to use the electronic thesaurus included in most computers’ word processing programs, but the best introduction in learning to use the thesaurus is the tried-and-true paper book. There are many other thesauruses besides the ones for literary use (and dictionaries too) with information about very specific or specialty subjects—psychology, art and architecture, food and agriculture, biology, etc. Teaching students to use simple paper reference books like the thesaurus and dictionary helps lay the foundation for navigating through other reference books and materials as well as their electronic counterparts with more efficiency and greater understanding.