By"-law` (bī"-l&add;`), n. [Cf. Sw. bylag, D. bylov, Icel. b&ymacr;arlög, fr. Sw. & Dan. by town, Icel. bær, byr (fr. bûa to dwell) + the word for law; hence, a law for one town, a special law. Cf. Birlaw and see Law.] 1. A local or subordinate law; a private law or regulation made by a corporation for its own government.

There was likewise a law to restrain the by-laws, or ordinances of corporations.
Bacon.

The law or institution; to which are added two by- laws, as a comment upon the general law.
Addison.

2. A law that is less important than a general law or constitutional provision, and subsidiary to it; a rule relating to a matter of detail; as, civic societies often adopt a constitution and by- laws for the government of their members. In this sense the word has probably been influenced by by, meaning secondary or aside.