A written law passed by the legislative branch of government—Congress or a state legislature—and usually signed into law by the head of the executive branch of government—the president or a state governor. When the executive "vetoes" (refuses to sign) a law, it can still become effective if the legislature has enough votes to "override" (defeat) the veto.
Statutes typically are gathered and arranged by subject matter in sets of books called "codes." Codes are a convenient way to study and research statutes. Today, codes can be found in both printed and electronic formats.