In classical conditioning, the response exhibited by a subject after he or she has been trained to associate a neutral (conditioned) stimulus with an unconditioned stimulus.
Example: In Pavlov’s classic dog experiments, the animals learned to associate the sound of a bell (the conditioned stimulus) with the presentation of food (the unconditioned stimulus). Eventually, the tone of the bell alone would elicit salivation (the conditioned response) from the dogs.
Grinnell, R. (2008). Conditioned Response. Psych Central. Retrieved on May 30, 2015, from http://psychcentral.com/encyclopedia/2008/conditioned-response/