http://en.wikipedia.org/wiki/Abstraction_(mathematics)
You see, we have a problem. Abstraction is already a term used in mathematics, in some ways referring to the opposite of surreality. It's almost a definitely of hyper-reality, reaching further into the preciseness of things and away from the normal experienced reality.
I suggest we go with the positive Cuil being a unit of surreality and leave the 'abstraction' for the general idea of separation from normal reality, whether it be positive Cuils (surrealism) or negative Cuils (mathematical abstraction, hyper-reality).