a part that is added to something to enlarge or prolong it

the railway's southern extension

a length of electric cable which permits the use of appliances at some distance from a fixed socket

a subsidiary telephone on the same line as the main one

you can listen on the extension in the bedroom

the action of moving a limb from a bent to a straight position

seizures with sudden rigid extension of the limbs

denoting instruction by a university or college arranged for people who are not full-time students

a postgraduate extension course

the range of a term or concept as measured by the objects which it denotes or contains

the property of occupying space

nature, for Descartes, was pure extension in space