IATE Term of the Week: Thesaurus


We celebrated Thesaurus Day on the 18th of January. This is the perfect occasion to take a deeper look into the origin of this type of reference book that is mainly used to diversify vocabulary. The term itself derives from the Greek word thésauros meaning treasure or treasure house. A very fitting word as logophiles consider the collection of synonyms and antonyms as a treasure chest. The early thesauruses (plural: Thesauruses or Thesauri) were in fact dictionaries. Let us start our journey with the origin of this useful work. Who created it?

The origin of the Thesaurus

There is a debate on who developed the very first thesaurus. The most probable theory of the very first thesaurus can be identified as a lost dictionary of synonyms that was written in the first century AD by the Greek historian, translator and grammarian Philo of Byblos. Furthermore, another work can be taken into consideration: an early Sanskrit thesaurus was written by a grammarian named Amara Sinha in the form of metric verse called The Amarakosha. Later, the age of the European Enlightenment gave birth to many attempts of different collections.

The very first modern Thesaurus: an invaluable reference tool

Thesauri came about in response to the desire of women and men of society to write and speak more fluently. Peter Mark Roget, a British doctor, lexical scholar, polymath and a fellow of the Royal Society, is credited with the authoring of the first lexicographical achievement: Roget’s Thesaurus. Peter was born in London in 1779, studied medicine at Edinburgh University and published medical works on sweating, tetanus, epilepsy as well as tuberculosis and on the effects of nitrous oxide, also known as ‘laughing gas’ that was used as an anaesthetic back then. Later in life, he started to branch out to other topics ranging from papers on Dante, the kaleidoscope or the game of chess.

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His thesaurus, one of the best-known reference works in English, started as a compilation of a list of words in 1805.  In 1840, Roget retired from his profession as a physician and spent the rest of his life working on the project called Roget’s Thesaurus of English Words and Phrases, a dictionary of synonyms. Actually, it can be seen as a reverse dictionary. You did not look for the exact word, but start with an idea and go through the book until you find a fitting word. His Thesaurus of English words and phrases; so classified and arranged as to facilitate the expression of ideas and assist in literary composition was published in 1852. The project is a comprehensive classification of synonyms or verbal equivalents, proved to be very successful already in his lifetime, and became the standard work. More than 30 million copies have been sold since the book was first published.

The biggest thesaurus in the world: The Historical Thesaurus to the Oxford English Dictionary – words and synonyms from Old English to the present day

Another very striking and massive undertaking over a period of four decades (44 years, 9 months and 1 week or 16351 days to be exact) is the thesaurus The Historical Thesaurus to the Oxford English Dictionary. The professor of English Language at Glasgow University, Michael Samuels, launched this project in 1965.230 people (editors, research assistants, postgraduate students, university staff and volunteers) were involved creating this impressive work on the variety and near-infinite richness of the English tongue that had cost 1 million pounds, plus uncosted academic time. Volunteers from Scotland and Germany and Canada were also recruited for this unique project. A fire in 1978 threatened to destroy the growing archive of entries, but luckily, the work could be saved. In 1981, a team of trainees started to store the data electronically. This dictionary of 4000 pages contains 804 830 entries arranged into over 125000 semantic entries. Linguists, lexicographers and language enthusiasts can discover at what point in time a specific term was coined and how long its lifespan was. Furthermore, this work offers a complete picture of the linguistic backdrop of the English language.

Let us take a very brief look at an example: the word potato. Chaucer, the father of English literature, would not have known about this vegetable as it was introduced to Europe in 1536, but it was known to Shakespeare. If you would like to know when a word was first used in English, this is the perfect source.

Chaucer and Shakespeare greatly influenced the entire English language and created an enormous amount of words in writing, but that would be another article.

IATE goes AUDIO page headerIATE goes AUDIO provides short audio clips in different languages explaining IATE Terms of the Week in a clear and concise manner. The aim of this initiative is to make IATE terminology accessible to a wider audience.

This week, you can tune in to another IATE goes Audio feature: click below to listen to ‘Thesaurus’ explained in English.


University of Glasgow. 2021. University of Glasgow: Story: Biography of Michael Samuels. [ONLINE] Available at: https://www.universitystory.gla.ac.uk/biography/?id=WH2254&type=P. [Accessed 21 January 2021].

Michael Samuels. 2021. Historical Thesaurus: About the Thesaurus. [ONLINE] Available at: https://ht.ac.uk/professor-samuels/. [Accessed 21 January 2021].

Hektoen International. 2020. Roget and his Thesaurus: a physician and a list maker. [ONLINE] Available at: https://hekint.org/2020/09/29/roget-and-his-thesaurus/. [Accessed 21 January 2021].

Project MUSE. 2007. Project MUSE – A history of Roget’s Thesaurus: Origins, development, and design (review). [ONLINE] Available at: https://muse.jhu.edu/article/218167/pdf. [Accessed 21 January 2021].

Merriam-Webster. 2021. The Remarkable Roget’s Thesaurus. [ONLINE] Available at: https://www.merriam-webster.com/words-at-play/rogets-thesaurus. [Accessed 21 January 2021].

BBC. 2014. BBC – History – Historic Figures: Peter Mark Roget (1779 – 1869). [ONLINE] Available at: http://www.bbc.co.uk/history/historic_figures/roget_peter_mark.shtml. [Accessed 21 January 2021].

Historical Thesaurus: About the Thesaurus. 2021. Acknowledgments. [ONLINE] Available at: https://ht.ac.uk/acknowledgements/. [Accessed 21 January 2021].

Historical Thesaurus: About the Thesaurus. 2021. Why a Historical Thesaurus. [ONLINE] Available at: https://ht.ac.uk/why/. [Accessed 21 January 2021].

Written by Victoria Milhan, Schuman Communication Trainee Terminology Coordination Unit. She holds master’s degrees in English Language (linguistics) and Medieval English Literature, Newer English Literature and Celtic Studies. Victoria is enrolled as a PhD student at Bonn University in Germany.