Classical Conditioning: This is a type of learning where an organism learns to associate two stimuli, leading to a new learned response. For example, if you ring a bell every time before feeding your dog, it will eventually start salivating at the sound of the bell alone.
Operant Conditioning: This is another type of learning where behavior is strengthened or weakened by the consequences that follow it. If your actions lead to positive outcomes, you're likely to repeat them; if they lead to negative outcomes, you'll probably avoid doing them again.
Reinforcement: This term refers to anything that increases the likelihood that a particular behavior will be repeated. It can be either positive (adding something pleasant) or negative (removing something unpleasant).