Until now there was no “standard” to define mirrorless system cameras. We had plenty of different definitions like:
– Digital Interchangeable Lens System Cameras (DILSC),
– Electronic Viewfinder with Interchangeable Lens (EVIL).
– Mirrorless System Cameras (MSC),
– Compact System Cameras (CSC),
– Digital Single Lens Mirrorless (DSLM).
But at last the Consumer Electronics Association (CEA) decision recognized “Mirrorless” as the official term for interchangeable lens cameras that do not include a mirror mechanism!
Amazing it took seven years to sort this out :)
Source: http://www.ce.org/Consumer-Info/TechnologyGlossary.aspx