Wiktionary
n. (context electronics English) An electrical cord with a plug one end, and a single socket or a multi-port socket at the other end, used for powering one or more devices at a distance, too far from the wall outlet to be reached by the normal cords of the device or devices.
WordNet
n. an electric cord used to extend the length of a power cord
Wikipedia
An extension cord, power extender, drop cord, or extension lead is a length of flexible electrical power cable (flex) with a plug on one end and one or more sockets on the other end (usually of the same type as the plug). The term usually refers to mains (household AC) extensions but is also used to refer to extensions for other types of cabling. If the plug and power outlet are of different types, the term "adapter cord" may be used. Extension cable is also used, but that has a distinct meaning from extension cord. Most extension cords range from around two to thirty feet in length although they are made up to 300 feet in length.
Usage examples of "extension cord".
The eldest Baudelaire grabbed the end of the extension cord and started to follow her siblings.
The edge of the farthest extension cord was bumping up against a piece of metal, all right--a metal lock.
As Attorney Alejandro promised, an extension cord has been plugged into a wall outlet near the cellblock entrance and run down the passageway and securely knotted around a pipe out of Randy's reach and the tail end of it allowed to trail across in the direction of the filing cabinet.
Corfe asked, plugging the drill into an extension cord from a power point set in a concrete post at the end of the dock.
When he found an outlet in the wall, he went to work on the extension cord with the wire cutters.
With the metal stock collapsed, the gun fit neatly into the tripod case, leaving room for spare ammunition in the zippered accessory pocket where Fitzduane normally kept his long remote extension cord.
Merton turned it off and strung a light from an extension cord, throwing the cord over a line just above the saw, so they could see what they were doing better.
The first thing to do is route your 12-volt extension cord(s) from the car through the nearest window.
Rick then took a 15-meter extension cord, about 45 feet long, plugged one end into the lamp fixture, and cut the female plug off the other end.
The lamp was hidden behind Keller's demonstration case, and the extension cord with the dynamite on the end was carried to the very edge of the cliff.