What does BACK, V mean?

BACK, V meaning in Law Dictionary

To indorse; to to remain the trunk; to signal typically by means of acceptance or approval. In which a warrant given within one county is presented to a magistrate of another county in which he signs it for the purpose of rendering it executory in his county, he could be thought to "back" it. 4 Bl. Comm. 201. So an Indorser of an email or costs is colloquially believed to "back" it. Seabury v. Hungerford, 2 Hill (N. Y.) 80.