Grey's has so many couples. Some have a name. Some don't. I say we name them all.

Meredith and Derek - MerDer, DerMer
George and Izzie - Gizzie, O'Stevens
Callie and Erica - Callica, EriCal
Mark and Lexie - Slexie, Sexie, Slexipedia, McSexie
Owen and Cristina - Huntina, Crowen, Owina
Izzie and Alex - Lexzie, Izzex, Azzie
Derek and Addison - Addek
Alex and Addison - Addex
Mark and Addison - Maddison
Callie and Arizona - Calizona
Denny and Izzie - Dizzie
Lexie and Alex - Alexie
Lexie and George - Gexie
Callie and George - O'Callie
Burke and Cristina - Burkina, Bang
Callie and Mark - Mallie
Mark and Izzie - McStizzie, Mizzie