a component that stores data so future requests for that data can be served faster; the data stored in a cache might be the results of an earlier computation (Wikipedia
information that does not contain any useful data, but serves to reserve space where real data is nominally present; can be used as a placeholder for both testing and operational purposes (Wikipedia)
the process of putting demand on a system or device and measuring its response; load testing is performed to determine a system’s behavior under both normal and anticipated peak load conditions (Wikipedia)
the amount of CPU and RAM your Web site can use on the server that you are on
a set of software subsystems or components needed to create a complete platform such that no additional software is needed to support applications; applications are said to "run on" or "run on top of" the resulting platform (Wikipedia)