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extension

n.
US //ɪkˈstɛnʃən// UK //ɛkstˈɛnʃən// ex·ten·sion
  1. 1 extra time (n.)
    B2 Upper Intermediate

    more time given to finish a task or a project.

    an additional period of time allowed for the completion of a task, often beyond an original deadline.

    Example

    The professor gave me a two-day extension on my essay because I was sick.

    Example

    The project manager requested a formal extension of the deadline, citing unforeseen delays in the supply chain that made the original schedule impossible.
  2. 2 building addition (n.)
    B2 Upper Intermediate

    a new room or part that is added to an existing building.

    a structural addition to an existing building that increases its total floor area or volume.

    Example

    They are building a kitchen extension to make more room for the family.

    Example

    The planning committee approved the rear extension on the condition that the materials matched the original Victorian brickwork.
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  1. 3 phone number (n.)
    B2 Upper Intermediate

    a short set of numbers used to reach a specific person in a large office.

    a subsidiary telephone line connected to a main switchboard, identified by a specific numerical code.

    Example

    If you need to speak to the manager, call the main office and ask for extension 402.

    Example

    The directory lists the direct extensions for every department head, allowing clients to bypass the automated reception menu.
    • internal line
  2. 4 software/computing (n.)
    B2 Upper Intermediate Computing

    a small program you add to a web browser or app to give it new features.

    a software module that adds specific features or functionality to an existing computer program or browser.

    Example

    I installed a browser extension that blocks annoying advertisements.

    Example

    The developer released a security extension designed to encrypt sensitive data before it is uploaded to the cloud storage service.
  3. 5 hair or nails (n.)
    B2 Upper Intermediate

    extra pieces of hair or material added to your own to make them look longer.

    artificial lengths of hair or synthetic material attached to a person's natural hair or nails for aesthetic purposes.

    Example

    She spent three hours at the salon getting hair extensions for the wedding.

    Example

    The stylist recommended high-quality silk extensions to ensure the final look appeared natural and blended seamlessly with the client's own hair.

    Usage

    Usually used in the plural form 'extensions'.
  4. 6 stretching a limb (n.)
    C1 Advanced Technical Medicine

    the act of straightening a part of your body, like an arm or a leg.

    the movement by which the two ends of any jointed part are drawn away from each other; the straightening of a limb.

    Example

    The physical therapist told him to focus on the full extension of his knee.

    Example

    Post-operative recovery protocols emphasize the gradual restoration of full extension in the elbow joint to prevent permanent stiffness.
    • flexion
  5. 7 file type (n.)
    B2 Upper Intermediate Computing

    the letters at the end of a computer file name that show what kind of file it is.

    a suffix consisting of a period and several characters at the end of a filename, indicating the file format.

    Example

    Make sure you save the document with a .pdf extension so everyone can open it.

    Example

    The operating system uses the file extension to determine which application should be launched by default when the user double-clicks the icon.
Origin

From Middle English extensioun, from Old French estension, from Latin extensiō, extensiōnem.

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