A push or pull exerted on an object which may change the object's state of motion is defined as:

The definition provided in the question describes force, which is a fundamental concept in physics. Force is defined as an interaction that, when unopposed, will change the motion of an object. It can cause an object to accelerate, decelerate, remain in place, or change direction, depending on the nature of the force applied.

For instance, pushing a car to get it moving, or pulling a sled are both examples of applying force to change the state of motion of those objects. The unit of force is the Newton, and it encapsulates the idea that it’s not only about exerting a push or pull but also about the potential effect that action can have on the movement of objects.

In comparison, work refers to the energy transferred through a force applied over a distance, energy is the capacity to do work, and power is the rate at which work is done or energy is transferred. None of these terms directly correspond to the action of applying a push or pull to an object in the same way that force does. Thus, force is the appropriate choice for this definition.