EVS - Electronic View System.
I was going to suggest LSD because my head was spinning from all the replies. I made a list of all the terms and letters, but I kept coming back to EVIL. It's exactly what is needed describe the class and differentiate if from SLRs & Rangefinders. Unfortunately, it's, well, EVIL. But then I had my eureka moment. Here's my list and reasoning:
D "Digital": NO. Film is dead. Move on. If anything, refer to old SLRs as fSLRs from now on.
E "Electronic": YES. Separates it from the optical finders (SLRs & Rangefinders).
V "Viewfinder" or "View": YES. Applies to both classes of cameras - with and without finders (since an LCD back can be thought of as a mini View camera).
C "Compact": NO. There is no reason why this type of camera has to be "compact". The only reason why it is is because the Micro 4/3 system didn't try to conform to 35mm full-frame lens mount and dSLRs did (even though most aren't full-frame). In other words, it's only describing a M4/3 system (which already has a name) compared to current dSLRs. But you can take a dSLR and replace the mirror & pentaprism with an EVF. Then what would you call it - a Non-Compact System Camera? Likewise, you can make a smaller SLR if you engineered it to an APS-C sensor.
Note - "C" can also mean camera, but that should be implied, as in "SLR Camera". Thus, a Compact System Camera should be called a CS Camera.
M "Mirrorless": NO. Can also mean "Mirror", plus I agree with the posting "You don't define something by saying what it hasn't got", especially since I think this will eventually be the dominant class of cameras as LCDs continue to improve (they are already better in several areas, and the best is yet to come).
L "Lens": MAYBE. It's kind of implied, but needed when used with "I".
I "Interchangeable": YES, but only when used with L, which unfortunately leads to EVIL.
S "System": EUREKA! It's an excellent alternative to "Interchangeable Lens". Just replace the IL in EVIL and you EVS - Electronic View System. That separates it from Optical finders (SLRs & Rangefinders), Mirrorless is not necessary, it's a System of Interchangeable Lenses, and it may or may not be Compact.
My job is done here. I can watch TV now.