The Superbowl - world champions or champions of the universe?

The American NFL, the National Football League is the premier American gridiron competition in the United States. I have found out the Superbowl is the final round from the National Football Conference and the American Football Conference.

So far, I am still getting it, the league is the highest professional level of American football in the United States with the NFC and ANC feeding into the main event. Of course, the Superbowl is the most famous game in the country with the winner becoming the league champion.

Just the name of the competition explains the competition parameters, the National Football League comprises of the American Football Conference and the National Football Conference - both leagues running in the United States with American teams playing against American teams.

What I don't understand is, why do the Americans refer to the Superbowl winner as champion of the world? These are American based teams playing in an American competition, a world championship or world cup is an individual or team representing their country at an elite level. Why can't they play for champion of the universe status instead?

Soccer is played all over the world, the 2014 soccer world cup will be held in Brazil with 32 nations qualifying for the competition, the United States is also represented - the best nation will win, now that's a world championship.

A point worth noting is the USA has not only made the cut in this soccer world cup, they have qualified for a number of competitions with their highest ever finish being third - a pretty handy stat for a nation that plays soccer as a secondary sport behind the NFL.

Has the Superbowl ever been played by a non-American team? Has the Superbowl ever been played outside of the United States? I would be interested to know.