Here are some possibilities, with nuances:
* γραφείο (grafio): This most closely translates to "desk" or "writing table," but it can be used colloquially to refer to a small office or the place where someone works.
* γραφεία (grafea): This is the plural of γραφείο, and is often used to refer to "offices" as in a business's offices.
* υπηρεσία (ypiresia): This translates to "service" or "department," and can be used to refer to a government office or a department within a company.
* λειτουργεία (leitourgeia): This refers to a "place of work" or a "service," and could be appropriate depending on the context.
Therefore, the best Greek word for "office" depends heavily on context. If you're translating a specific sentence, providing the context will help determine the most accurate word.