Superconditioning is a term associated with classical conditioning. It occurs when a conditioned stimulus and an unconditioned stimulus are paired in the presence of a previously established conditioned inhibitor.
For instance, imagine Pavlov's dogs being taught to respond to a bell that is associated with receiving food. However, they can also be unintentionally conditioned to associating other stimuli to receiving that same food (for example seeing the person that feeds them, hearing footsteps or doors closing, etc) that occur within the same time frame as a scheduled feeding time. In this example superconditioning involves the addition of extra, and unintentional, stimuli that the animals would also respond in lieu of the bell signals.