Bylaws is spelled both with and without a hyphen. For example, Black’s Law Dictionary gives a definition for bylaw but notes that it’s sometimes spelled by-law.
So which is preferable?
It appears that bylaw is gaining the upper hand. For example, the 1915 edition of Robert’s Rules of Order Revised used by-laws but the current edition, Robert’s Rules of Order Newly Revised, uses bylaws. And althought its predecessor used by-laws, the new Massachusetts Business Corporation Act, effective 2004, uses bylaws.
So I say by-laws is dead. Long live bylaws!
Of course, lawyers are behind the times, as usual. Last month, 626 contracts filed as “material contracts” on the SEC’s EDGAR system used by-law; only 135 used bylaw.
But note that there are other wrinkles to bylaws. Here’s what Garner’s Modern American Usage has to say:
Both the spelling and the sense differ on the two sides of the Atlantic. In AmE, bylaws are most commonly a corporation’s administrative provisions that are either attached to the articles of incorporation or kept privately. In BrE, bylaws are regulations made by a local authority or corporation, such as a town or a railway.
The spelling without the -e- is preferred in AmE. Though etymologically inferior, byelaw (sometimes hyphenated) is common in BrE.