Verbs and Adjectives to Nouns: The Evolution of Headwords in Encyclopedias from the Late Seventeenth to the Late Nineteenth Century.

This article investigates the historical shift in encyclopedias from including various parts of speech as headwords—such as verbs and adjectives—to predominantly using nouns from the late seventeenth to the late nineteenth century. This change, part of the partial differentiation of encyclopedias from dictionaries, was driven by three main factors: the expansion of historical content categorized mainly under nouns, a move away from specialized terminology toward broader conceptual coverage, and efforts to standardize headwords to improve user accessibility. While early encyclopedias and proto-encyclopedias accepted diverse grammatical forms as headwords, nineteenth-century general encyclopedias like the Encyclopaedia Britannica and Brockhaus's Konversations-Lexikon largely restricted headwords to nouns. The article also notes that specialized encyclopedias retained more non-noun headwords due to their focus on technical terminology, but overall, the trend toward nominalization reflected evolving editorial priorities and user needs in reference works.