From Medieval Latin or Late Latin theodiscus, from a Germanic language, ultimately from Proto-Germanic *þiudiskaz (“of the people, popular, vernacular”), from *þeudō (“people”) + *-iskaz (“-ish, -ic, -al”). The Old English form is þēodisċ, the Old High German one diutisc (attested ca. 1090 in the Annolied). Compare also Friulian todesc, archaic or regional French thiois, Sicilian tudiscu.