Information that makes more forcible or convincing. Synonym:reinforcement.
2.
A military operation (often involving new supplies of men and materiel) to strengthen a military force or aid in the performance of its mission. Synonyms:reinforcement, support.
... 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