Definitions of regulation:

• noun:   the act of controlling or directing according to rule

  Example: "Fiscal regulations are in the hands of politicians"

• noun:   the act of bringing to uniformity; making regular
• noun:   an authoritative rule
• noun:   (embryology) the ability of an early embryo to continue normal development after its structure has been somehow damaged or altered
• noun:   the state of being controlled or governed
• noun:   a principle or condition that customarily governs behavior

  Example: "Short haircuts were the regulation"

• adjective:   prescribed by or according to regulation

  Example: "Regulation army equipment"