What term describes an automatic nerve reaction to a stimulus that produces movement?

The term that describes an automatic nerve reaction to a stimulus that produces movement is "reflex." A reflex action is an involuntary and nearly instantaneous movement in response to a stimulus, often processed by the spinal cord instead of the brain. This rapid response is crucial for protecting the body from harm; for example, if you touch something hot, the reflex will cause you to withdraw your hand before you even consciously register the pain.

In contrast, the other terms, while related, do not specifically describe this automatic reaction. An impulse refers to the electrical signal that travels along a nerve, a reaction often entails a broader range of responses and can require conscious thought or decision-making, and a response is generally a more conscious reaction to stimuli that may be voluntary. Therefore, "reflex" is the most precise term to describe an automatic nerve reaction producing movement.