The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name molar derives from Latin, molaris dens, meaning millstone tooth, from mola, millstone and dens, tooth. Molars show a great deal of diversity in size and shape across mammal groups. The third molar of humans is a vestigial organ, as it has lost its original function.