Informed Comment

FAI’ في
Booty obtained from infidels. According to Muhammad ibn Tahir, fai’ is booty taken from a country which submits to Islam without resistence, as distinguished from ghanimah, or plunder. The Khalifah ‘Umar said it was the special privilege of the Prophet to take booty as well as plunder, a privilege not permitted to any other prophet.
‘Ani ibn Malik says the Prophet used to divide the booty on the same day he took it, and would give two shares to a man with a wife, and only one share to a man without one. (Mishkat, book xvii c xii.)

Based on Hughes, Dictionary of Islam