Final answer:
The pairing of a neutral stimulus with an established conditioned stimulus to create a new conditioned response is referred to as higher-order conditioning in the context of classical conditioning.
Step-by-step explanation:
When a neutral stimulus (NS) is paired with an already established Conditioned Stimulus (CS), and the NS becomes a CS, this is called higher-order conditioning. Higher-order conditioning occurs in classical conditioning, when a stimulus that does not initially elicit a response is connected with an unconditioned stimulus to become a new conditioned stimulus. This process continues beyond the simple pairing of basic stimuli, thus allowing the formation of a conditioned response to a stimulus that has not been directly paired with an unconditioned stimulus.