Contemporary art is work (painting, sculpture time based media etc) intentionally created, then exhibited and peer reviewed as contemporary art within the last twenty years.
Contemporary art COULD be used to mean art produced today, but museums which say they show contemporary art usually mean art produced after World War II.
Art is somebody else's Creative Expression, in the form of there own imagination, and is percieved how each individual percieves it. The Definition changes with each art piece as art is different...