A term used in the Roman law to denote a forced or compulsory service exacted by the government for public purposes ; as a forced rendition of labor or goods for the public service. See Dig. 50, 4, 18, 4. In maritime law. A forced service, (onus,) imposed on a vessel for public purposes; an impressment of a vessel. Loco, de Jure Mar. lib. 1, c. 5, §§ 1-6. In feudal law. Any troublesome or vexatious personal service paid by the tenant to his lord. Spelman.