›[C or U]an increase in the period of time during which something is effective: grant/offer/receive an extensionWhen it failed to meet the deadline, the company was granted an extension.a three-month/two-year, etc. extensionextension to sthThe company has negotiated an extension to the deadline for its £275 million cash-and-paper offer, originally expected tomorrow.
›[C or U]the fact of giving or offering something to someone: This cheap, available money led to the extension of credit around the world.
›[C](abbreviationext., abbreviationxtn)COMMUNICATIONSone of the phones in a large building that have their own numbers and are connected to a switchboard (= a piece of equipment used to direct all phone calls): Please give me a call back at extension 1247.Can you put me through to Jan Robert's extension, please?
›[C or U]an increase in the size or range of something: Most banks are recognizing that customers view Internet banking as an extension of existing services.We are committed to the extension of this tax credit to cover all children born after April 2010.The engineers have begun working on an extension of the canal.
›[C]IT the last part of the name of a computer file, which comes after a dot (.), and shows what type of file it is: Be sure to leave the file extension unchanged.
›[C]UK(USaddition)a new part that is added onto a building: The bank syndicate will finance a $460 million extension to the car factory.