(n.) The chief officer of a regiment; an officer ranking next above a lieutenant colonel and next below a brigadier general.

ADC CO OD aide aide-de-camp brigadier brigadier general captain chicken colonel chief of staff commandant commander commander in chief commanding officer commissioned officer company officer exec executive officer field marshal field officer first lieutenant five-star general four-star general general general officer generalissimo jemadar junior officer lieutenant lieutenant colonel lieutenant general major major general marechal marshal officer one-star general orderly officer risaldar senior officer shavetail sirdar staff officer subahdar subaltern sublieutenant the Old Man the brass three-star general top brass two-star general