• noun something added to something else to make it longer
  • An enlargement in scope, or in length of time. For instance, a plug in which adds functionality to an application.
  • A set of characters appearing at the end of a filename, indicating the file type. For example, in the filename notepen.exe, the .exe portion is the extension, and in this case specifies an executable program. Also called filename extension.
  • A telephone, modem, or similar device connected to a main line, such as a PBX.

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