A mortgage which creates a lien on two or more pieces of property. Blanket mortgages are often used by individuals or companies that have more than one piece of real estate, and that want to take out a mortgage or second mortgage on the combined value of their properties. For example, a real estate developer with several undeveloped lots could mortgage those lots in order to build homes on them. Instead of taking a mortgage on each property, the real estate developer takes out one mortgage on the combined value of the properties.