Test Coverage refers to the measure of how much of a software application is tested by automated or manual tests. It helps ensure that all parts of the application are evaluated for bugs and issues, which can improve the overall quality of the software. Test coverage can be expressed as a percentage, indicating the proportion of code or features that have been tested. There are different types of test coverage, including code coverage, which focuses on the lines of code executed during testing, and requirements coverage, which assesses whether all specified requirements have been tested. By analyzing test coverage, teams can identify untested areas and prioritize their testing efforts effectively.