10 Things (Findings, Facts) You Didn’t Know About the Thesaurus

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Whether in print or online, the thesaurus is the friend of readers, writers, and students trying to come up with alternatives for the word “said” (hint: spoke, articulated, voiced). A useful tool for writing, a thesaurus is also a key part of understanding how language is classified, allowing us to see the ways in which words relate to one another and how synonyms develop over time. They can also serve as resources for language learners, who use thesauri (yes, that is the plural, though thesauruses is also acceptable) to better understand how words relate to one another. Especially with the advent of online and open-source versions, thesauri can adapt to new uses of language and help lexicographers understand how the meanings of words evolve.

Of course, the thesaurus can also turn what should be a simple message into a transparent memorandum, so it’s important to be careful (and/or circumspect) in their use. However, when used properly, a thesaurus can be not only a way to vary word choice in writing but also an opportunity to look at how language is organized. As you’ll see from the facts below, early authors of thesauri worked to apply scientific and philosophical concepts to words, in order to classify the constantly shifting concept that is how we read, speak, and write. Read on to find out more about these fascinating texts.

Roget’s Thesaurus is the Most Used Thesaurus in the English-Speaking World

Created in 1805 and first published in 1852, this well-known book was created by Peter Mark Roget, a retired physician from London. While the first edition contained “only” 15,000 words, the newest, eighth edition contains 443,000 words and is updated consistently to stay current with new uses of language.

Roget’s Was Not the First Thesaurus to be Publicly Available

The Amarakosha is a thesaurus in ancient Sanskrit by the scholar Amarasimha, most likely sometime in the 6th century, and it is one of the earliest surviving examples of a textbook of language organization. Additional earlier thesaurus-like books included John Wilkin’s Alphabetical Dictionary (1668), which grouped synonyms together, Hester Lynch Piozzi’s British Synonymy (1794), and George Crabb’s English Synonyms Explained (1818). Each of these books was mostly focused on helping writers find synonyms directly, rather than classifying words as Roget did. Some early thesaurus authors, like Wilkin, also hoped that the study of language and synonyms would lead to the creation of a universal language that would be used by people of different nationalities and backgrounds to communicate with one another.

Roget May Have Been Influenced by His Mental Health

Peter Mark Roget was born in Soho, London, and he lost his father at a young age. He then trained as a physician and practiced for a few decades before retiring and preparing the thesaurus for publishing starting in 1840. It was theorized by his biographers that Roget suffered from long-term depression and that his classification system, which would eventually become the thesaurus, arose from Roget keeping notebooks of word lists as a coping mechanism.

Roget Led a Varied Life

In addition to his word classification work, Roget also participated in a study of the spread of disease at London’s infamous Millbank Penitentiary, wrote papers denouncing the pseudo-science of phrenology, and helped found the University of London. After leaving medicine, he served as the first secretary of the Portico Library, designed a portable, pocket chess board, and published papers on optical illusions and the emerging field of moving images.

The term for a “thesaurus” has Latin and Greek roots…

“Thesaurus” comes from the Latin thēsaurus, which is from Greek θησαυρός (thēsauros), meaning “treasure, treasury, or storehouse.” Prior to the 19th century, the term thesaurus was often also used to refer to dictionaries or encyclopedias. It is Roget who is credited with defining it broadly as a “collection of words arranged according to sense.”

…and is used in other fields to mean something else altogether.

While most people associate the thesaurus with finding synonyms, the term is also used in library and information science, where it refers to a type of controlled vocabulary, and in natural language processing, where it is used to provide context-based simplification for automated translations.

Roget’s Classification Schemes Relied on the Work of Leibniz and Aristotle

To classify words and their synonyms, Roget used a four-level taxonomy based on 1000 Conceptual Heads. Heads were then crossreferenced throughout the text, and direct synonyms were noted. In creating his taxonomy, Roget referenced works such as Aristotle’s Categories (which lists all of the things that can possibly be the subject or the predicate of a proposition) and the work of famous mathematician Gottfried Wilhelm Leibniz on representing symbolic thought and logic.

Roget’s is Not the Only Thesaurus

While Roget’s work has become synonymous with the modern thesaurus in many ways, other types do exist. Collins Thesaurus, for example, is an online version that includes abilities for translation and is compiled by lexicographers with the aim to reflect global variations in the English language. Merriam-Webster also publishes a thesaurus, that includes antonyms, near antonyms, and synonym usage examples. Oxford publishes a thesaurus designed for writers, with versions for American English and British English. Multiple specialized thesauri also exist in a variety of subjects.

An Open Source Thesaurus Exists

The Moby Project is a public-domain lexical resource that aims to be the “largest free phonetic database.” Its thesaurus project consists of 30,260 root words, with 2,520,264 synonyms all stored in comma-separated value format, and calls itself “the largest thesaurus in the English language.”

Many Thesaurus Creators Were Inspired by Utopian and Utilitarian Philosophies

When Roget published the first edition of his thesaurus he wrote that he had begun the project in order to “supply my own deficiencies” and hoped it would help other writers do the same. Roget, and other thesaurus authors like Wilkin, were drawn to the philosophy of Utilitarianism, which prioritized maximizing the happiness and well-being of those involved with a dilemma or situation. Thesaurus creators hoped that by simplifying and classifying language, they would make both writing and language learning easier for their users.

Eager to learn more? Check out these dictionary and thesaurus apps, learn how words are added to the dictionary, and read more about the history of the thesaurus.