Microsoft Office is an example of a closed-source software.
Closed source (or proprietary software) means computer programs whose source code is not published. The source code is not shared with the public for anyone to look at or change. Closed source is not open source, but some software is neither, because open source also implies the freedom to redistribute.
Examples of closed source software for commercial use are Microsoft Office, Adobe Acrobat, McAfee anti-virus software, and so on. Examples of closed source software not distributed commercially would be proprietary software used to operate a proprietary operation at a bank or a factory.