What is the term applied to reciprocating circular motion like that of a pendulum?

The term that applies to reciprocating circular motion, such as that observed in a pendulum, is oscillation. This is characterized by repetitive swinging or movement back and forth around a central point. In the case of a pendulum, the motion consists of a continuous, periodic change in position as it swings from one extreme to another and returns, following a curved path.

Oscillation describes the behavior of systems that exhibit this repetitive motion, typically around a fixed point, which is a fundamental concept in various fields of physics and engineering. Recognizing this term is essential in understanding various mechanical systems and their behaviors, particularly in structures subject to vibrations and movements.

Other terms, such as intermittent motion, refer more to on-off or paused motion rather than the smooth, continuous pattern seen in oscillation. Reciprocating motion usually involves linear movements back and forth and doesn't apply to circular paths. Momentum is a broader concept related to the quantity of motion an object has, and while it may be relevant in discussing the motion of a pendulum, it does not specifically describe the type of movement itself. Thus, oscillation is indeed the correct term for this context.