The act of reenforcing, or the state of being reenforced.
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.
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.
... her philosophical way; "ye're no thinking that Mister Hollister is an officer, and stands next the cornet, in the troop. But this piddler gave warning of the brush the night, and it's no sure that Captain Jack would have got the day, but for the reenforcement." ... — The Spy • James Fenimore Cooper