The Century dictionary, an encyclopedic lexicon of the English language, William D. Whitney, 1895

8 volumes - 7 000 pages - 260,000 entries

The Century Dictionary is “designed to be a practically complete record of the main body of English speech, from the time of the mingling of the Old French and Anglo-Saxon to the present day”, including “technical terms of the various sciences, arts, trades, and professions”. It offers “definitions proper of such related encyclopedic matter” with the addition of “pictorial illustrations”.

Links to the books at archive.org

Consult also the Century dictionary supplement