A snickerdoodle is a type of cookie made with flour, butter or oil, sugar, salt, and rolled in cinnamon sugar. Eggs are sometimes used, with cream of tartar and baking soda added to leaven the dough. They are characterized by a cracked surface, and can be crispy or soft.
Snickerdoodles are sometimes called "sugar cookies". But, sugar cookies are rolled in white sugar while snickerdoodles are rolled in a mixture of white sugar and cinnamon.