A standardized test is a test

Test (assessment)

A test or an examination is an assessment intended to measure a test-taker's knowledge, skill, aptitude, physical fitness, or classification in many other topics . A test may be administered orally, on paper, on a computer, or in a confined area that requires a test taker to physically perform a...

 that is administered and scored in a consistent, or "standard", manner. Standardized tests are designed in such a way that the questions, conditions for administering, scoring procedures, and interpretations are consistent and are administered and scored in a predetermined, standard manner.

Any test in which the same test is given in the same manner to all test takers is a standardized test.