master class

• masterclass

From master +‎ class. First use appears c. 1861 in the publications of John Stuart Mill.

master class (plural master classes)

1. (education) A class, typically in a performing art such as music or drama, in which a teacher listens to and critiques the performance of individual students, one at a time, while the other students observe.
   • 1929, Tillman Breiseth, “Arias for Angels”, in North American Review, page 95:

     The vocal pedagogue loves the Master Class idea. Such classes are usually conducted by the more plutocratic teachers for periods of from two to six weeks. Many of them vaguely promise to deliver a complete technique within that time.

2. (figuratively) An action or series of actions that serve to demonstrate a person's mastery of a subject.
3. A brilliant or virtuosic performance.