An ~ is a new room or building which is added to an existing building or group of buildings.
An ~ is a new section of a road or rail line that is added to an existing road or line.
...the Jubilee Line ~.
N-COUNT: usu with supp
An ~ is an extra period of time for which something lasts or is valid, usually as a result of official permission.
He first entered Britain on a six-month visa, and was given a further ~ of six months...
Something that is an ~ of something else is a development of it that includes or affects more people, things, or activities.
Many Filipinos see the bases as an ~ of American colonial rule...
N-COUNT: usu N of n
An ~ is a telephone line that is connected to the switchboard of a company or institution, and that has its own number. The written abbreviation ext. is also used.
She can get me on ~ 308...
N-COUNT: also N num
An ~ is a part which is connected to a piece of equipment in order to make it reach something further away.
...a 30-foot ~ cord...