The terms “mortgage”, “mortgagee”, “mortgagor”, “maturity date”, and “State” shall have the meanings respectively set forth in section
1707 of this title, except that the term “mortgage” for the purposes of subsection (c) this section may include a first mortgage given to secure the unpaid purchase price of a fee interest in, or a long-term leasehold interest in, a one-family unit in a multifamily project, including a project in which the dwelling units are attached, semi-attached, or detached, and an undivided interest in the common areas and facilities which serve the project where the mortgage is determined by the Secretary to be eligible for insurance under this section. The term “common areas and facilities” as used in this section shall be deemed to include the land and such commercial, community, and other facilities as are approved by the Secretary.