Money deposited as security to ensure that some event occurs or does not occur. For example, in landlord tenant law a security deposit is collected by a landlord from a tenant to ensure that the final month’s rent has been paid and that the tenant has left the premises in the same condition as the property was given to the tenant (less reasonable wear and tear) and that the landlord will not wrongfully incur repairs as a result of damages caused by the tenant’s departure. Payment made to a landlord by a tenant (usually an amount equivalent to one or two month’s rent) to ensure that the tenant stays current in paying the rent and that the residential unit remains in good condition, even after the tenant moves out of the premises. Damage to the premises is usually deducted from the security deposit.