MARRIAGE, n. The state or condition of a community consisting of a master, a mistress and two slaves, making in all, two.

Ambrose Bierce (1842–1914?) American writer and journalist

“Marriage,” The Devil’s Dictionary (1911)
    (Source)

Originally published in the "Cynic's Word Book" column in the New York American (1904-08-13), and the "Cynic's Dictionary" column in the San Francisco Examiner (1904-11-15).