The Structure of the Historical Thesaurus of the OED

'I can hardly imagine any reference book more valuable … here is the information we had to spend hours hunting down through the thickets and coverts of the great OED, shot, stuffed, and mounted for us.'
Philip Pullman

HTOED is organized into three major sections, reflecting the main activities and preoccupations of users of the language:

I The external world II The mental world III The social world

These in turn are divided into 354 major categories, such as Food and drink, Thought, or War. Further categories and subcategories follow, moving from the most general ideas to the most specific. Overall, HTOED contains almost 800,000 meanings, organized into more than 236,000 categories and subcategories.

The semantic categories and subcategories are headed by phrases which define them and link to preceding sections. In the abridged example below, the headings and numbering show that Terms of endearment, at the fourth level of the semantic hierarchy, are part of Love, which is classified within the higher category of Emotion, which in turn comes under The mind. In some cases, the hierarchy descends in six or seven levels (indicated by the same number of numerals segmented by full stops), with synonyms represented at every level.

02 The mind …. 02.02 Emotion …. 02.02.22 Love …. 02.02.22.04 Terms of endearment ….

The final printed work is presented in two volumes: Volume 1 is the Thesaurus itself, organized according to the semantic categories outlined above, while Volume 2 is an alphabetical Index listing the majority of the synonyms in Volume 1. Readers may thus approach the content of the Thesaurus in different ways: either by looking up a single lexical item in the Index and being directed to the appropriate section in the main Thesaurus, or by browsing by semantic category directly, and seeing words in their context of both historical development and the overall organization of meaning.

'Finally the OED has a worthy counterpart.'
Ammon Shea