SADAQA
The word sadaqa is derived from sidq meaning truth, and comes to signify a charitable deed, occurring 14 times in the Koran. Sometimes the terms zakat and sadaqa are wrongly used in the same sense. Sadaqa denotes a voluntary alms. According to Koran (9:14): "Take from their property alms (sadaqa) in order thus to purify them (tuzakki'him)." Sadaqa is a mere generic term applying to the alms.
Source
Encyclopaedia of Ismailism by Mumtaz Ali Tajddin