Clock pendulum and Physical pendulum

Clock pendulum noun - A physical pendulum used to regulate a clockwork mechanism.

Physical pendulum and clock pendulum are semantically related. In some cases you can use "Physical pendulum" instead a noun phrase "Clock pendulum".

Physical pendulum noun - Pendulum consisting of an actual object allowed to rotate freely around a horizontal axis.

Clock pendulum and physical pendulum are semantically related. Sometimes you can replace phrase "Clock pendulum" with "Physical pendulum", this phrases are similar.