Русско-англо-русский юридический словарь

A legal mortgage arises when the assets are conveyed to the secured party as security for the obligations, but subject to a right to have the assets reconveyed when the obligations are performed. (Wikipedia)

Pay a booking fee of £50 and a security deposit (as security for the performance of the Tenant’s obligations) of £150 and a pre-payment of rent of £300 on returning a signed copy of this Agreement to the Landlord. (Tenancy Agreement 2014/2015, digstudent.co.uk)