Humans have 12 molars in total, in four groups of three at the back of the mouth. The molar which is the farthest back in each group is called a wisdom tooth. The wisdom teeth are the last teeth to appear, usually at around the age of eighteen. These final molars do not erupt in many people.
All molars and premolars have a structure for grinding food. They have elevated (~pointed) parts called cusps. These cusps are characteristics of the species in question, but in general they are found on the molars, and to a lesser extent on premolars.