'Jacken' is a shipping name used to represent the relationship between Captain Jack Harkness and Gwen Cooper.
These two people are fictional characters in sci-fi show called Torchwood, created by Russell T. Davies.
Many fans ship this pairing, but since Janto has gone canon, many have supported Janto instead.
'Jacken' is a joining of Jack's and Gwen's names; the 'Jack' from.. Jack, and the 'en' from Gwen.
Jack and Gwen have shared 2 kisses in the first series of Torchwood, in the episode 'Day One' and the other in the finale, 'End Of Days.'
'OMFG that shooting scene in Ghost Machine was SOOO HAWT, Jacken is like.. *THUD*'
'Awww, Jacken kiss.. *loves*'