Definition of augen in English:

augen

Pronunciation /ˈaʊɡ(ə)n/

noun

Geology
  • Flattened oval or lens-shaped mineral grains present in some metamorphic rocks, notably augen-gneiss. Chiefly attributive, indicating the presence of such grains, as "augen-schist", "augen structure", etc.

Origin

Late 19th century; earliest use found in Nature: a weekly journal of science. From German Augen, specific use of the plural of Auge eye.