The careers are the young people who are chosen to go to the Hunger Games from the wealthier districts. They are called 'careers' because they have been trained for years to go to the Hunger Games -- they have made it their career to prepare for the time when they are ready for their own Games. They volunteer to go to the Games because they have been told since birth that it is a great honor to go and potentially die in the cause of the Games. Because the Games are done for the amusement of the people of the Capital, the careers and their districts are seen as more closely connected to the Capital. The careers have money to specifically train for their survival in the games; they are given better gifts from the fans of their district; therefore, they do have a better chance of survival in comparison to the tributes from the poorer districts, but in the end there are no guarantees and all but one must die. Katniss survives on her natural talents and instincts.
In the Hunger Games, the "careers" is the nickname given to the tributes who are trained to enter the Games. These are the districts that regularly win the games. In those districts it is seen as an honor to play in the Games, while in other, less fortunate, districts, like Katniss's, it is a nightmare. The careers are practically groomed from birth to play in the games. The train for every possible scenario the could face in the arena. The are well-fed, well-built and all around best suited to win the games.
"Career Tributes" refer to the tributes who have spent the majority of their lives training to represent their district in the annual Hunger Games. They generally come from the more affluent Districts - 1, 2, and 4 - and are relatively put-together (probably because they volunteered in the first place) compared to the other tributes. At the beginning of the Games, the Careers band together, picking off the other weaker, less-trained tributes. This also explains why Careers tend to win the Hunger Games.
Also, If you are looking for specific names/districts, the careers in The Hunger Games are Glimmer, the female from District 1, Cato, the male from District 2, and Clove, the female from District 2. The names for the boy from District 1 and the boy and girl from district 4 are not given. Generally, the careers are the tributes from Districts 1, 2, and 4.
The careers are ones that have been trained for the Hunger Games . So when it's time for the reaping , they volunteer. Careers are the ones that usually end up winning in the end.
The careers are the children that are especially trained for the role of being in the hunger games. They are trained for being in the Hunger Games for their whole life, and when the time comes around to be chosen for it, they volunteer. These people are despised by people from other districts, because they usually dont include themselves, but usually end up being the winner of the Hunger Games. The careers usually team up at the beginning of the Games, and hunt down the weaker tributes, and then later turn on each other, for the hope of winning the Hunger Games.