The Historical Thesaurus of the Oxford English Dictionary (HTOED) is the print edition of the largest thesaurus in the world, the Historical Thesaurus of English (HTE), conceived and compiled by the English Language Department of the University of Glasgow. The HTE is a complete database of all the words in the second edition of The Oxford English Dictionary, arranged by semantic field and date. In this way, the HTE arranges the whole vocabulary of English, from the earliest written records in Old English to the present, alongside types and dates of use. It is the first historical thesaurus to be compiled for any of the world's languages and contains 800,000 meanings for 600,000 words, within 230,000 categories, covering more than 920,000 words and meanings. As the HTE website states, "in addition to providing hitherto unavailable information for linguistic and textual scholars, the Historical Thesaurus online is a rich resource for students of social and cultural history, showing how concepts developed through the words that refer to them."
On 22 October 2009, after 44 years of work, version 1.0 was published as a two-volume set as HTOED. It consists of two slipcased hardcover volumes, totaling nearly 4,000 pages. The HTE, released as version 4.2 in September 2014, is freely available online from the University of Glasgow.
The work is divided into three main sections: the External World, the Mind, and Society. These are broken down into successively narrower domains. The text eventually discriminates more than 236,000 categories. The second order categories are: