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.

(algebra, Galois theory) An algebraic extension that is both a normal and a separable extension; equivalently, an algebraic extension E/F such that the fixed field of its automorphism group (Galois group) Aut(E/F) is the base field F.

Alternative form of overextension.

Alternative form of underextension.

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

plural of extension table

plural of extension block

(telecommunications) The transmission path originating from the interface of the access provider's side of a telecommunications circuit Demarcation Point within a premise and ending at the termination point prior to the interface of the edge Customer Premises Equipment. This may include in-segment equipment, media converters and patch cords as required to complete the circuit's transmission path to the edge CPE.