Zeuss, Johann Kasper (1806-1856), philologist and grammarian; born in Vogtendorf in southern Germany. After a delicate and bookish childhood he studied at Munich University. Having first completed an impressive work on the German peoples, he turned to the Celtic languages, and especially Irish. He studied the interlinear glosses in the devotional Latin tracts of central European monasteries frequented by early Irish monks. From these he developed an ordered grammatical system, published as Grammatica Celtica (Leipzig, 1853).

(yō'hän käs'pär tsois) , 1806–56, German philologist. Zeuss's principal scholarly achievement was his establishment of the basis for the study of Celtic in his Grammatica celtica (1853, in Latin). Totally ignored by the academic world, he was still teaching in a high school when he died.