i Register
In some senses, mirrorless is marked as rare. Watch for register when choosing this word.
adj
Without a mirror.
Not mirrored; unreflective.
one would discover in her eyes, large, protruding and clear, that mirrorless look of polished metals which report not so much the object as the movement of the object.
noun
A mirrorless interchangeable-lens camera, similar to a digital SLR, but usually made smaller by incorporating an electronic viewfinder instead of a mirror and prism.