An examination is a special test to see how good somebody is at something.
In its widest sense, to examine somebody or something is look at it very carefully, perhaps to find out why something is not working properly. Someone who is ill may need to go to a doctor to have a medical examination. A machine that is not working properly may need an examination to find out the cause of the problem.
In education an examination (or exam for short) is a test to show the knowledge and ability of a student. A student who takes an examination is a candidate. The person who decides how well the student has performed is the examiner. An examination may be a written test, an on-screen test or a practical test. Examples of a practical test may be: driving a car, speaking a language, playing a musical instrument and doing a scientific experiment. An on-screen test is a test which uses the computer.
If the candidate is successful he will have passed the examination. If he is unsuccessful he will have failed. In some cases it is possible for a student who has failed to take the exam again another time.
A student who passes an examination may get a certificate or diploma. Some certificates are professional qualifications, allowing the person to do a particular job, e.g. plumber, teacher, doctor, lawyer.