An example of a crystal is a piece of amethyst in its natural form.
An example of a crystal is an antique European wine glass with cut out ornamentation.
A crystal lake; the crystal clarity of their reasoning.
"Do I make myself clear?" / "Crystal."
An example of crystal used as an adjective is the phrase "crystal lake" which means a lake where there is no garbage, pollution, etc. ruining the color or clarity of the water.
Origin of crystal
- Middle English cristal from Old French from Latin crystallum from Greek krustallos ice, crystal kreus- in Indo-European roots
From American Heritage Dictionary of the English Language, 5th Edition
- Old English cristal (“clear ice/mineral”), from Latin crystallum (“crystal, ice”), later reinforced from Anglo-Norman cristall, Middle French cristal, from Latin crystallum, from Ancient Greek κρύσταλλος (krustallos, “clear ice”), from κρύος (kruos, “frost”), from the Proto-Indo-European *krus-, *kru- (“hard, hard outer surface, crust”).