1. Being, relating to, or composed of crystal or crystals.
2. Resembling crystal, as in transparency or distinctness of structure or outline.

[Middle English cristallin, from Old French, from Latin crystallinus, from Greek krustallinos, from krustallos, ice, crystal.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.