KHIYAR خيار
“Option.” A term used to express a certain period after the conclusion of a bargain, during which either of the parties may cancel it. According to ‘Abdu ‘l-Haqq, it is of five kinds: (1) Khiyaru ‘sh-Shart, optional condition; where one of the parties stipulates for a period of three days or less. (2) Khiyaru ‘l-A’ib option from defect; the option of dissolving the contract on discovery of defect. (3) Khiyaru ‘r-Ru’yah, option of inspection; the option of rejecting the thing purchased after sight. (4) Khiyaru ‘t-Ta’yin, option of determination; where a person, having purchased two of three things of the same kind, stipulates a period to make his selection. (5) Kiyaru ‘l-Majlis, the option of withdrawing from the contract as long as the meeting of the parties continues. The Hanafiyah doctors do not accept the last, but it is allowed by the other sects.

Based on Hughes, Dictionary of Islam