The term 'SPUR DISC' is a combination of two words, 'SPUR' and 'DISC'. The first word, 'SPUR', is a type of metal or leather-covered projection that is attached to the heel of a rider's boot and used to urge a horse forward. The second word, 'DISC', is a flat, round object, usually made of metal or plastic, with a hole in the middle. When combined, the term 'SPUR DISC' refers to a ROWEL, which is a small, star-shaped wheel with sharp points that is attached to the end of a SPUR and used to encourage a horse to move faster.