K-line Definition
    noun
  
 Origin of K-line
-  Short for kill line, and refers to the line in an IRC daemon's configuration file, prefixed with a k, that records a user's hostname to prevent further access to the server From Wiktionary 
Short for kill line, and refers to the line in an IRC daemon's configuration file, prefixed with a k, that records a user's hostname to prevent further access to the server
From Wiktionary