A wild-card playoff team is a team that is entered into the postseason play of a given sports league despite not winning its own division. In the NFL, which is divided into the National Football Conference and the American Football Conference, and then into North, South, East and West divisions within each conference, there are two wild card teams added to the four division winners in each conference. The division winners make it into the playoffs regardless of their record, while the teams with the two best records among non-division winners each qualify as a wild-card playoff team.
The first round of the NFL playoffs is often referred to as the Wild Card round. It features the two wild card teams playing against the two lowest-seeded division winners. The winners of those two games then play the top two division winners in the Divisional round. Those top two teams have the advantage of having to win one less game to get to the Super Bowl.
Major League Baseball uses a similar system, though there is only one wild-card playoff team to go with the three division winners in the National League and the American League. In the first round of playoffs, the team plays the division winner with the best record, unless the teams are in the same division, while the other two division winners play each other. The winners of those series go on to face each other in the League Championship Series, the precursors to the World Series.
The NFL began using the wild card system in 1970, and in the first 35 years, only four wild card teams won the Super Bowl. The 1980 Oakland Raiders were the first wild-card playoff team to win the Super Bowl, beating the Philadelphia Eagles. The 1997 Denver Broncos, 2000 Baltimore Ravens and 2005 Pittsburgh Steelers also each won the Super Bowl as a wild-card playoff team.
Wild card success is more common in baseball than in football, perhaps partly because wild card teams do not have the disadvantage of having to win one more game than the top teams, like they do in the NFL. Baseball began using the wild card in 1995, and the first wild-card playoff team to win the World Series was the 1997 Florida Marlins. There was even a stretch, from 2002 to 2004, that saw a wild-card playoff team win the World Series for three straight years, and the 2002 Series pitted two wild card teams, the Giants and the Angels.
Non-division winners are allowed into the playoffs in all four major American team sports, but it is not always referred to as a wild card. In the NBA and NHL, there only three division winners and five of what would be considered wild-card playoff teams in each conference, so the term "wild card" is not used.