Microsoft codenames are the codenames given by Microsoft to products it has in development, before these products are given the names by which they appear on store shelves. Many of these products (new versions of Windows in particular) are of major significance to the IT community, and so the terms are often widely used in discussions prior to the official release. Microsoft usually does not announce a final name until shortly before the product is publicly available. It is not uncommon for Microsoft to reuse codenames a few years after a previous usage has been abandoned.
There has been some suggestion that Microsoft may move towards defining the real name of their upcoming products earlier in the product development lifecycle so as to avoid needing product codenames.
|Codename||Preliminary name||Final name||Notes|
|Kato, Sparta||Windows for Workgroups 3.1|
|Snowball (LB)||Windows for Workgroups 3.11|
|Chicago/Cougar||Windows 4.0||Windows 95||-||O'Hare||Internet Explorer, first shipped in Microsoft Plus! for Windows 95||The codename O'Hare ties into the Chicago codename for Windows 95: O'Hare International Airport is the largest airport in the city of Chicago, Illinois — in Microsoft's words, "a point of departure to distant places from Chicago"Cite error: Closing </ref> missing for <ref> tag.|