'By-law' definitions:

Definition of 'By-law'

From: GCIDE

By-law \By"-law`\ (b[imac]"-l[add]`), n. [Cf. Sw. bylag, D. bylov, Icel. b[=y]arl["o]g, fr. Sw. & Dan. by town, Icel. b[ae]r, byr (fr. b[^u]a 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. [1913 Webster]
There was likewise a law to restrain the by-laws, or ordinances of corporations. --Bacon. [1913 Webster]
The law or institution; to which are added two by-laws, as a comment upon the general law. --Addison. [1913 Webster]
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. [1913 Webster]