Werner Hüllen. English Dictionaries 800–1700: The Topical Tradition / Werner Hüllen. A History of Roget's Thesaurus: Origins, Development, and Design.

Abstract

Under section 559. Word, my edition of Roget's Thesaurus includes a sub-paragraph: dictionary, lexicon, wordbook, word-stock, word list, glossary, vocabulary; gradus, thesaurus, wordhoard; compilation, concordance, index. (Roget 1984) The semi-colons between vocabulary and gradus and between wordhoard and compilation are crucial. They indicate a relationship looser than synonymy. They signify that dictionary and thesaurus are not interchangeable.