Under Section 58(a) of the Transfer of Property Act, 1882, a "mortgage" is defined as:

Section 58(a) of TPA, 1882 defines "mortgage" as the transfer of an interest in specific immovable property for the purpose of securing the payment of money advanced or to be advanced by way of loan, an existing or future debt, or the performance of an engagement which may give rise to a pecuniary liability. The person transferring the interest is the "mortgagor," the person to whom it is transferred is the "mortgagee," the principal money and interest of which payment is secured is the "mortgage money," and the instrument (if any) is the "mortgage deed." A mortgage differs from a pledge (movable property under Sections 172–179 of the Indian Contract Act, 1872) and from a charge under Section 100 of TPA where no transfer of interest occurs. TPA, 1882 recognises six types of mortgages under Sections 58(b) through 58(g).