What is the definition of "impetus"?

The term "impetus" refers to a moving force or stimulus that drives an action or reaction. It is often used in contexts where there is a motivation or energy behind a process or activity, suggesting that something is propelling action forward. Whether in a physical sense, such as an object in motion gaining momentum, or in a metaphorical sense, such as ideas or projects gaining support or traction, "impetus" highlights the dynamic quality of whatever is initiating movement or change. This aligns perfectly with the concept of a moving force, making this choice the most accurate representation of the word's definition. The other options do not capture this essence of active movement or drive.