I want to buy a memory card for my sony w55 but dont know what PSP means on the memory card?

Answer 1

PSP stands for Sony's video game system, the Play Station.

The card will probably work in your Sony camera too. Ask or read further.

Good Luck

Answer 2

It means the card you are buying is a memory stick (pro) duo and that the PSP supports it.
(PSP = Playstation Portable.)

I do not know if your camera supports duo, so you should make sure, though the cards usually come with in an adapter that allows you to use than as if they were memory stick pros.
(If you don't have one, you can find them at Best buy.)