The delivery date is one of several features of a futures contract, which references the spot month; this is the date on which the parties are required to complete the terms of the contract. Delivery on a contract is typically determined on a specific day or days of the month; trading in the futures contract comes to an end on or prior to the delivery date.
For example, the Brent Crude oil futures which are traded on the International Petroleum Exchange in London have monthly delivery dates over the next 12 months, quarterly delivery dates for the following 12 months and half-yearly dates for the following year afterwards.
Trading in the Brent Crude oil futures for a specific delivery month stops trading on the trading day immediately before the 15th day before the first business day of the delivery month. This delivery month is also referred to as the spot month as this is when the commodity may be delivered to settle the contract.