The "test case pass rate" is a metric used in software testing to measure the percentage of test cases that have successfully passed during a testing cycle. It is calculated by dividing the number of passed test cases by the total number of test cases executed, then multiplying by 100. A higher pass rate indicates better software quality and fewer defects. This metric is essential for software development teams as it helps assess the effectiveness of their testing efforts. By monitoring the test case pass rate, teams can identify areas that need improvement and ensure that the software meets the required standards before release.