Microsoft Word is a word processing program developed by Microsoft. It was first released on October 25, 1983, under the original name Multi-Tool Word for Xenix systems. Subsequent versions were later written for several other platforms including IBM PCs running DOS (1983), Apple Macintosh running the Classic Mac OS (1985), AT&T UNIX PC (1985), Atari ST (1988), OS/2 (1989), Microsoft Windows (1989), SCO Unix (1990), Handheld PC (1996), Pocket PC (2000), macOS (2001), Web browsers (2010), iOS (2014), and Android (2015).
Microsoft Word has been the de facto standard word processing software since the 1990s when it eclipsed WordPerfect. Commercial versions of Word are licensed as a standalone product or as a component of Microsoft Office, which can be purchased with a perpetual license, as part of the Microsoft 365 suite as a subscription, or as a one-time purchase with Office 2024.