Cocaine is an alkaloid which is derived from coca leaves, most of which are grown in South America.
It is a stimulant drug affecting the central nervous system. It is similar in it's effect to amphetamines. Crack is a processed form of cocaine which has been treated so that it can be absorbed into the bloodstream more rapidly. This is a term invented by the media to describe a baby whose mother used cocaine or crack during her pregnancy. Reputable professionals do not describe children this way.