DCHP-2

bylaw by-law, by law, byelaw, bye law DCHP-2 (March 2017)

• n. — Politics, Administration

  a law made by a body subordinate to a legislature, usually a municipal government.

  Type: 5. Frequency — The spelling variant bylaw is not exclusive to Canada and is marked in the COD-1 as "Cdn, Brit. & Austral.". However, this variant, bylaw, appears to be most prevalent in Canada (see Chart 1), as is by-law (see Chart 2). In official writing in Canada, however, the hyphenated form is nearly universally used.
  See also Gage-1, s.v. "by-law" (1), and OED-3, s.v. "by-law" (2), DAE, s.v. "bylaw".