Some words look like English, but they are Chinese
What is the real meaning of PK? 


Yes, PK is a kind of Chinglish (Chinese English).


  日常生活中，PK的常见含义有：
  
  
  对决，对抗；
  击败，淘汰；
  泛指两件对等事物的比较，对比。
  


(PK's common meanings include: 1. confrontation/battle; 2. knock out; 3. comparison).


  这个词较初起源于MUD游戏中的Player Killer（PKer，指游戏中专门杀害其他玩家的人），后衍生出Player Killing（指随便杀人之意），引申为“玩家对战”。


(The word stemmed from "Player Killer" in MUD, then derived as "Player Killing", extended in meaning of battle between Players (Player VS Player).)


  还有一种说法称，PK起源于足球里的罚点球，即Penalty
  Kick的缩写，引意为一对一单挑，只有一方能赢。但这一起源的认可度不及网络游戏起源说。


(Another version is that PK stemmed from "Penalty Kick" in soccer game, extended to meaning of one-on-one challenge.)