Premises are land and buildings together considered as a property. This usage arose from property owners finding the word in their title deeds, where it originally correctly meant "the aforementioned; what this document is about", from Latin prae-missus = "placed before". In this sense, the word is always used in the plural, but singular in construction. Note that a single house or a single other piece of property is "premises", not a "premise", although the word "premises" is plural in form; e.g. "The equipment is on the customer's premises", never "The equipment is on the customer's premise".