n. 1. The act of reenforcing, or the state of being reenforced. [ 1913 Webster ]

2. That which reenforces; additional force; especially, additional troops or force to augment the strength of any army, or ships to strengthen a navy or fleet. [ 1913 Webster ]

3. (Psychology) A reward or punishment which is given to a person or animal in order to increase the likelihood that a specific behavior will be repeated. [ PJC ]