Punches are hand tools that were originally designed to punch holes when struck by a hammer. They are also used to make a mark where some future action will take place or for removing pins, nails or rivets.
A punch is a straight tool that is meant to be struck with a hammer or mallet--like a chisel. It has a blunt end so it makes a hole of mark when struck. If it tapers to a smaller diameter, is called a tapered punch--these are used to concentrate the force of the hammer blow into a small space. If it is not tapered, is called a parallel punch.
A parallel punch is used to remove an object that has already been loosened by a tapered punch. Parallel punches are also used to mark a spot on wood or plastic thart will be drilled at some future time. Parallel punches usually come in sets of various sizes.
Pin punches are specifically designed to remove pins. A parallel pin punch is used to remove a pin that is loosened by a tapered pin punch or by some other means.