show ring
Flat rectangular grounds where the competitors perform their tests; each routine must be executed in precise time, sometimes to music.
chief steward 
President of the jury who is located behind the C marker letter; during a school test, the chief steward rings a bell when a competitor commits an error in the course.
marker letter 
One of several signs placed around the ring at regular intervals; they act as reference points for the rider during the execution of the figures.
judge 
Person in charge of evaluating the performances; five judges (including a president) are positioned around the ring and score each figure out of 10.
course steward 
Official in charge of enforcing the rules and overseeing that the competition unfolds smoothly.