Usability testing is a technique used in user-centered interaction design to evaluate a product by testing it on users. This can be seen as an irreplaceable usability practice, since it gives direct input on how real users use the system. wikipedia.org

Regression testing is any type of software testing that seeks to uncover new errors, or regressions, in existing functionality after changes have been made to a system, such as functional enhancements, patches or configuration changes.

Web testing is the name given to software testing that focuses on web applications. Complete testing of a web-based system before going live can help address issues before the system is revealed to the public. wikipedia.org

Functional testing is a type of black box testing that bases its test cases on the specifications of the software component under test. Functions are tested by feeding them input and examining the output, and internal program structure is rarely considered (Not like in white-box wikipedia.org

Compatibility testing is a part of non-functional testing conducted on application software to ensure the application's compatibility with different computing environment wikipedia.org

Databases are the collection of files which are interconnected. Databases at different servers may not be of same type, i.e. databases may be heterogeneous.

End-to-end testing is a methodology used to test whether the flow of an application is performing as designed from start to finish. The purpose of carrying out end-to-end tests is to identify system dependencies and to ensure that the right information is passed between various system components and systems. wikipedia.org

Mobile application testing is a process by which application software developed for hand held mobile devices is tested for its functionality, usability and consistency. wikipedia.org

Manual testing is the process of manually testing software for defects. It requires a tester to play the role of an end user, and use most of all features of the application to ensure correct behavior. wikipedia.org

Test management most commonly refers to the activity of managing the computer software testing process.

A bug tracking system or defect tracking system is a software application that keeps track of reported software bugs in software development projects. It may be regarded as a type of issue tracking system. wikipedia.org

A test case in software engineering is a set of conditions or variables under which a tester will determine whether an application or software system is working correctly or not.

Software testing is an investigation conducted to provide stakeholders with information about the quality of the product or service under test. wikipedia.org

Black-box testing is a method of software testing that tests the functionality of an application as opposed to its internal structures or workings (see white-box testing). Specific knowledge of the application's code/internal structure and programming knowledge in general is not required. wikipedia.org