Meaning of CRYSTAL in English

CRYSTAL

crys ‧ tal /ˈkrɪstl/ BrE AmE noun

[ Date: 1000-1100 ; Language: Old French ; Origin: cristal , from Latin crystallum , from Greek krystallos 'ice, crystal' ]

1 . [uncountable] very high quality clear glass:

a set of six crystal glasses

2 . [countable] a small regular-shaped piece of a substance, formed naturally when this substance becomes solid:

ice crystals

copper sulphate crystals

3 . [uncountable and countable] rock that is clear, or a piece of this

4 . [countable] American English the clear cover on a clock or watch

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.