In real estate, the term perfect generally refers to the legal process of making a lien, mortgage, or other security interest enforceable and legally binding against third parties. This process is known as perfection of the security interest. When a lien or mortgage is “perfected,” it means that the creditor’s interest in the property has been formally established, usually through registration or filing with the appropriate government authority, making it public and giving the creditor priority over other potential claims on the property.