Why is it called a Wii?

I was planning on saving up for an iPod this month, and buying it later on in Feb. However I think I would get more use from the new Wii. I played at a friends house last night, that thing is sooooooooo much fun. I actually beat her, meaning it is simple because I can count the number of times on one hand that I have picked up a controler for any video game. Fun, Fun, Fun!!!