Software build
When a software application is created and major updates are made, a version number is often assigned to the software. Developers also add a software build number to the version every time the software is built. The software build acts like a sub-version number. Patches for fixing bugs, issues (mostly small issues, but sometimes larger issues also), and sometimes even minor feature additions often result in a change to the software build.
Keeping software up-to-date requires knowledge of the latest software build and downloading and installing the patch corresponding to it. Also, when needing technical support for a software application, the support staff often ask for the software build for your software to better assist with issues or general help. Issue resolution may be dependent on the software build, as some issues are specific to the details of one particular build of the application.