Okay. This is what about.com had to say about the what defines a pump and where the name came from.
What are Pumps?
History of Pumps
Eventually, bows and other embellishments, as well as heels were added to pumps, making them more feminine than the flat, plain shoes from which they originated.
Retro Leopard Print Peep Toe Pumps
Leopard Print Peep Toe Pumps