Bosses are characters in video games that are more powerful than other enemies. They usually appear at the end of a world or area, and must be beaten to get to the next part of the game. Sometimes, bosses are easy to defeat, and other times they are difficult to defeat. Some bosses, such as Bowser from the Mario series are famous and well-known, while others, like Gooper Blooper, also from the Mario series, aren't well-known and famous.
The term "boss" came from how most of the time bosses are the bosses of the enemies. Although in games like Crash TwinSanity the bosses aren't always bosses at all. Just other characters that you run into in your path. In racing games like CTR bosses are called champions and the player is forced to win a race against them. Although in most games bosses are beaten by depleating their health bar, or just out living them. Bosses also sometimes fight the player with their minions although most prefer to fight by their lonesome.