Web-applications are designed to be accessed through the internet and are not required to be installed on a user's device.
A mobile application, also known as an app, is a type of application software created specifically for mobile devices like smartphones and tablet computers.
Cloud computing is the on-demand, pay-as-you-go delivery of IT resources over the Internet.
Software testing is a technique to make sure the final product is free of errors and that it actually complies with the expectations.