Monogamy
From BiblePortal Wikipedia
Webster's Dictionary [1]
(1): ( n.) Single marriage; marriage with but one person, husband or wife, at the same time; - opposed to polygamy. Also, one marriage only during life; - opposed to deuterogamy.
(2): ( n.) State of being paired with a single mate.
Hastings' Dictionary of the New Testament [2]
See Marriage.
