A crowbar is a metal tool used mainly to pry things open. It is usually hook shaped. Sometimes the bottom is slightly curved to allow for better leverage. Some crowbars have a notched an end for removing nails. Crowbars are often made of carbon steel. They can also be made of titanium which is lighter and non-magnetic. The first known use of the word was somewhere in the 1400s where they were simply called crows or iron crows.