A watch powered by a wound spring rather than a battery, its rate set by an oscillating balance wheel and balance spring.
A mechanical watch stores energy in a wound mainspring and transmits it through a train of wheels. The escapement releases that energy in controlled steps and supplies impulses to the balance and balance spring, whose oscillation sets the rate. Winding replenishes the stored energy. A hand-wound watch uses manual winding, while an automatic watch uses an oscillating weight to wind the spring as the watch moves. Both belong to the mechanical category. Lubricants deteriorate over time, so servicing concerns the condition of the mechanism as well as whether the watch is currently running.
In job listings
Harrods’ Quality Control Associate role in London called for basic mechanical watch movement knowledge and listed Level 20 Rolex Accreditation as desirable. This places the concept within a technical knowledge requirement for quality control. The accreditation would be an advantage. The employer did not make it compulsory or specify individual inspection procedures. Search local jobs for “mechanical watch”.