Find accurate definitions of over 5,000 Catholic terms and phrases (including abbreviations). Based on Fr. John Hardon's Modern Catholic Dictionary, © Eternal Life. Used with permission.
An act of sexual intercourse between a man and a woman who are not validly married, although they are free to marry. It is by its nature gravely sinful. (Etym. Latin fornicatio, fornication; from fornix, a vault, arch, brothel.)