1) Systematic influence of an antecedent stimulus (or set of stimuli) on the probability of occurrence of a response. The response form or frequency differs from under one controlling stimulus, or set of stimuli, to another. These controlling stimuli are referred to as discriminative stimuli.

2) A change in operant behavior that occurs when either an SD or S^ is presented. When an SD is presented, the probability of response increases; and when an S^ is given, operant behavior has a low probability of occurrence.

3) The increased probability of a discriminated behavior that is produced by a stimulus (SD).

4) (complete). A phenomenon described by a very high probability of behaviors occurring (or not occurring) in the presence of particular antecedent stimuli, and a very low (or higher) probability of occurring in their absence.

5) A phenomenon, inferred by observing, that the antecedent stimulus does not consistently regulate the behavior (i.e., the behavior does not reliably occur or fail to occur, respectively, in response to the presence or absence of the stimulus).

6) The tendency for the target behavior to occur in the presence of the SD but not in the presence of the S-delta.

7) The control that stimuli in our environment acquire over the behavior we emit in their presence.