Continuous-Integration (CI) is the process of merging developer's working code copies to a shared codebase frequently to prevent or minimize integration problems. For questions about a specific CI system like [Jenkins] or [Travis-CI] use those tags instead.
Continuous-Integration (CI) is the process of merging developer's working code copies to a shared codebase frequently and test it to prevent or quickly identify and resolve integration problems. The idea is that developers write and commit small pieces of code and check several times a day if their code alterations break existing functionality.
There are many (server) systems that facilitate continuous integration and the work they do is often also called continuous integration. This usually includes (but is not limited to) code compilation and executing unit and integration tests. Some often-used CI software includes:
A comparison of CI software can be found on Wikipedia.
Use this tag for questions about continuous integration in general. For questions about specific CI software, it's best to use the tag for that system (if one exists).