(1) For multifamily housing, the HUD/FHA agreement to insure construction advances for multifamily housing projects subject to compliance with the terms of the commitment. HUD/FHA issues a firm commitment for mortgage insurance after accepting complete, final development drawings including complete specifications and firm costs. (2) The HUD/FHA agreement to insure a loan taken out by a borrower on a specific, previously approved single family property under specific terms. (3) For loans, a lender's agreement to make a loan to a specific borrower under specific terms and conditions within a given time. (4) In the secondary mortgage market, a buyer's agreement to purchase mortgage securities under specified terms.