extension

n. 1 extending or being extended. 2 part enlarging or added on to a main building etc. 3 additional part. 4 a subsidiary telephone on the same line as the main one. B its number. 5 additional period of time. 6 extramural instruction by a university or college.

v. t. The act of extending or the state of being extended; a stretching out; enlargement in breadth or continuation of length; increase; augmentation; expansion.