The words test and testing have many meanings:

• Testing (experimentation) is part of the scientific method: A test is a comparison of an expectation with an observation. The expectation must be known (written down, sketched, enumerated, communicated, etc.) before the observation is known; otherwise, the raw observation does not qualify as an experiment. But, if the raw expectation is made explicit, then it can become material for a hypothetical explanation of the subject under study. A test differs from a measurement, which is a comparison to a standard (--William Shockley).
• In manufacturing, quality assurance testing is a procedure designed to test the functionality of the product under potentially harmful conditions. This product is frequently called the unit under test, or UUT. In semiconductor IC final testing, the semiconductor device is frequently referred to as the device under test or DUT. (Every memory chip in the computer you are using to read this Wikipedia has been tested at least twice by very expensive testing equipment and testing programs. )
• In education, a test is a tool or technique intended to measure students' performance, knowledge or skills.
• The river Test is a river in Hampshire, England.
• Test is also the professional wrestling name of Andrew Martin.