Significat

1. mirror, looking-glass (smooth surface, usually made of glass with reflective material painted on the underside, that reflects light so as to give an image of what is in front of it)
2. smooth and shiny water surface
3. light stain on the backside of deer, fallow deer, and roes
4. spot on the wingtips of capercaillies and black grouse, and on the flight feathers of wild ducks