What is the meaning of Crystal?

A solid composed of an array of atoms or molecules possessing long-range order and arranged in a pattern which is periodic in three dimensions.

A piece of glimmering, shining mineral resembling ice or glass.

A fine type of glassware, or the material used to make it.

Crystal meth: methamphetamine hydrochloride.

a person's eye.

The glass over the dial of a watch case.

Made of crystal.

Very clear.

Source: wiktionary.org