A table (furniture) constructed so that it can be extended or contracted in length.

plural of extension table

(mathematics, logic) An extension of a logical theory such that every theorem expressible in the original theory is also derivable within the original theory.

(computing) A file extension.

(Scouting) A program within Scouting which caters for young people with special needs.

plural of Extension Scout

(Scouting) A youth member of the Extension Scouting program.

A short series of text characters at the end of a computer filename, used to indicate the type of contents and the software that will be required to operate or open it.

(nautical) An attachment to the tiller that enables the helmsman to steer from further forward on the boat.

(electronics, US) 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.