lalalala~~~~!Ah, oh my god.It is the abbreviation of "Player Killing", It used as a noun, then gradually can be used as a verb. As word spread last several years of the Talent-show's success like "Super-girl", this word "PK" is becoming more and more popular. The meaning of this word in the TV Show including "Challenge to a contest" and "the person graded last in the performance evaluation will be laid off from his position". That's all.

ELF的中文解释很对 英文的。。。

PK在英文里是Player Killer的简称，意思是“玩家杀手”,后引申为动词,player kill,意为游戏中杀人。也就是说，PK指的是在游戏中杀死其他玩家的玩家，是一个名词。但引入中国后，由于人的误解，通常把它作为一个动词来使用，有攻击和对打的意思。例如:“我和你PK”，“我昨天被PK了”。 现在也有单挑的意思，现在PK一词的含义变得越来越广，有的人甚至连打架斗殴也用PK来形容。 现在网络游戏中PK 经常是指 PLAYER KILL 意思是玩家之间的彼此对打，一般网络游戏都支持玩家PK ，而且有的游戏还有群P，就是所谓的打群架（足球里PK是指PERSONAL KICK意思是点球） PK is a Player Killer in English where the short, which means "player killer", the latter extended to the verb, player kill, meaning to kill the game. In other words, PK refers to the killing of other players in the game players, is a noun. However, the introduction of China, due to people's misunderstanding, it is usually used as a verb, meaning to attack, and the rally. For example: "I'm with you PK", "Yesterday, I was a PK." But now they have singled out the meaning of the meaning of the term PK is now becoming more and more widely, and some people even fighting and is also used to describe the PK. Now online games are often refers to the PK mean PLAYER KILL between players fight each other online games in general support the players PK, but there are some games group P, is the so-called gang war (football where PK is the meaning of PERSONAL KICK is a penalty) If the translation is inaccurate, please forgive me

I think is "penalty kick"