mid-14c., "the customary and unwritten laws of England as embodied in commentaries and old cases" (see common (adj.)), as opposed to statute law. Phrase common-law marriage is attested from 1909.
common law originated in the unwritten laws of England and was later applied in the United States
commodious
commoditization
commodity
commodore
common
common law
common sense
commonality
commoner
commonly
commonness