The Promptorium parvulorum (Latin: "Storehouse for children") is an English-Latin bilingual dictionary that was completed about 1440 AD. It was the first English-to-Latin dictionary.^[1] It occupies about 300 printed book pages.^[2] Its authorship is attributed to Geoffrey the Grammarian, a friar who lived in Lynn, Norfolk, England.^[3]

After the invention of the printing press, the Promptorium was published repeatedly in the early 16th century by printer Wynkyn de Worde.^[3] In the 19th century, the Camden Society republished it under the extended title Promptorium parvulorum sive clericorum (“Storehouse for children or clerics”).^[1] For language historians it is a major reference work for the vocabulary of late medieval English. It is a frequently cited reference in today's primary dictionary of late medieval English, the Middle English Dictionary, published by the University of Michigan.

• Catholicon Anglicum, an English-to-Latin dictionary dated 1485