No, they aren't the same thing. A visa is something that is in your passport or accompanies your passport. Usually, when you get a visa, documentation of that visa is put on one of the many blank pages of your passport by the authorizing official. So, if I'm American, I get my passport from the United States government, but if I want to travel to Brazil, for example, then my visa comes from Brazil, normally via a Brazilian consulate that they've located in the United States.
Basically, your passport is the document that gets you back into your home country, whereas your visa is the document that gets you into the country you want to visit. Your visa is usually in your passport because you'll need your passport to get back home and other countries generally accept foreign passports as proof of identification, proof that the visa they've issued is actually yours.