What is the origin of the idiom "on the dot" and when to use it?

The phrase "on the dot" originated from the field of timekeeping and punctuality. The term "dot" refers to a precise point or moment in time, often represented by a small mark or dot on a clock or timekeeping device. It is commonly used to indicate strict adherence to a specific time or deadline, whether it's for meetings, appointments, public transportation schedules, or events.