Microsoft Office is a set of interrelate desktop applications, servers and services, collectively referred to as an office suite, for the Microsoft Windows and Mac OS X operating systems. Office was introduced by Microsoft in 1989 on Mac OS, with a version for Windows in 1990. Initially a marketing term for a bundled set of applications, the first version of Office contained Microsoft Word, Microsoft Excel, and Microsoft PowerPoint. Additionally, a "Pro" version of Office included Microsoft Access and Schedule Plus. Over the years, Office applications have grown substantially closer with shared features such as a common spell checker, OLE data integration and Microsoft Visual Basic for Applications scripting language. Microsoft also positions Office as a development platform for line-of-business software under the Office Business Applications (OBA) brand.