n. That department of an army the duties of which consist in supplying transport, provisions, forage, camp equipage, etc., to the troops; also, the body of officers in that department.n. The office or employment of a commissary.n. In Scots law, the jurisdiction of a commissary; the district of country over which the authority or jurisdiction of a commissary extends. See extract.Pertaining to or concerned in furnishing supplies: as, the commissariat department; commissariat arrangements.