A late-medieval Anglo-Saxon manuscript glossary, illustrated with some drawings to clarify meanings, introduces a tradition of pictorial illustration in printed English dictionaries, a tradition that began on a small scale in the seventeenth century, when it first received theoretical justification. Although the leading lexicographer Samuel Johnson in the eighteenth century and the authoritative New (later Oxford) English Dictionary in the nineteenth century eschewed pictorial illustration, such images flourished in encyclopaedias and also in dictionaries produced by the Merriam-Webster Co. in the US. During the twentieth century special dictionaries for students of English as a second language, including several published by Oxford University Press, made ready use of pictorial illustration, and the practice of including selected pictorial illustrations continues to be popular in standard dictionaries. Although space in a printed dictionary is severely limited, and no single picture can adequately illustrate the name of a thing, lexicographical inquiry conducted online can now generate a more informative array of images that together can better illustrate the meaning of a word.