Regulation (-lshn), n.
1. The act of regulating, or the state of being regulated. The temper and regulation of our own minds. Macaulay.
2. A rule or order prescribed for management or government; prescription; a regulating principle; a governing direction; precept; law; as, the regulations of a society or a school. Regulation sword, cap, uniform, etc. (Mil.), a sword, cap, uniform, etc., of the kind or quality prescribed by the official regulations.
Syn. -- Law; rule; method; principle; order; precept. See Law.
Shades of meaning
Fernald has no entry of its own for regulation; he lists it under law.
He lists it without comment; the entries above explain its neighbors.