Definition of Napoleonic code in US English:

Napoleonic code

noun

  • A legal code established by Napoleon I and based on Roman law, which was introduced in 1804 and still constitutes the French civil law code; (also in extended use) any of a number of other legal systems which are derived from this, such as the civil codes of Louisiana and Quebec.

Origin

Mid 19th century; earliest use found in Harper's Magazine. After French code Napoléon.