n. Orderly government or system; system of order; government; control.n. Any regulation or remedy which is intended to produce beneficial effects by gradual operation; specifically, in medicine, the regulation of diet, exercise, etc., with a view to the preservation or restoration of health, or for the attainment of a determinate result; a course of living according to certain rules: sometimes used as equivalent to hygiene, but most commonly used as a synonym for diet, 2.n. In zoology, habit or mode of life with regard to eating; choice of food; dietetics: as, an animal or a vegetable regimen; carnivorous regimen.n. In grammar: Government; the control which one word exercises over the form of another in connection with it.n. The word or words so governed.n. In physical geography, the physical characteristics of a river, especially of a graded river; also, the condition of a river or current when it does not actively build up or wear down its course; in general, grade. See the extract.