The term 'Pendulum Setting' is a process used to adjust the timekeeping accuracy of a pendulum clock. The process involves adjusting the length of the pendulum, which is done by moving the bob up or down the rod. The PIT acronym stands for 'Pendulum In Time', which is a method of adjusting the pendulum setting to ensure that the clock keeps accurate time. This is done by adjusting the length of the pendulum until the clock runs at the correct speed.