What is the literal sense of the German voice classification system used to identify voice types?
Voice type:  Voice classification is often used within opera to associate possible roles with potential voices. Fach: The German Fach system (] ; literally "compartment" or "subject of study", here in the sense of "vocal specialization") is a method of classifying singers, primarily opera singers, according to the range, weight, and color of their voices.
vocal specialization