Diez, Friedrich Christian (frē'drikh kris'tyän dēts) [key], 1794–1876, German philologist. A professor at Bonn, Diez is noted as one of the founders of the science of Romanic philology. His great works were a grammar of the Romanic languages (1836; later much enlarged) and a dictionary of the Romanic languages (1853; also much enlarged in later editions).