A one-time payment made by a tenant to a landlord or property owner, often in addition to a deposit and rent, especially in Japanese rental agreements. Can also refer to a premium paid for acquiring a right or lease.
This apartment requires key money in addition to the security deposit.
I paid a premium to acquire the business rights for that shop.
Compound of 権利 (right, claim) and 金 (money). The term likely originated in Japanese real estate practice to describe a payment for the right to lease or use a property.