n The act of extending or the state of being extended; a stretching out; enlargement in breadth or continuation of length; increase; augmentation; expansion.
n That property of a body by which it occupies a portion of space (or time, e.g. "spatiotemporal extension")
n (semantics) Capacity of a concept or general term to include a greater or smaller number of objects; — correlative of intension.
n (banking|finance) A written engagement on the part of a creditor, allowing a debtor further time to pay a debt.
n (medicine) The operation of stretching a broken bone so as to bring the fragments into the same straight line.
n (weightlifting) An exercise in which an arm or leg is straightened against resistance.
n (fencing) A simple offensive action, consisting of extending the weapon arm forward.
n (telecommunication) A numerical code used to specify a specific telephone in a telecommunication network.