The time taken by the pendulum to go back and forth the whole swing is called the time period of a pendulum.
Step-by-step explanation:
A pendulum is a heavy object tied to a string and being suspended from a height. This structure can be moved a certain distance about its resting position which results in a periodic motion of this object, also called the simple harmonic motion. This motion takes a particular time to get completed and that is called the time period of the pendulum. The distance covered on each half of the motion is called the mean position is called the amplitude and the number of complete movements done by the pendulum in 1 second is called as its frequency.