General English

General Science


  • noun a regular geometric shape formed by minerals, or as water freezes


  • noun a small slice of quartz crystal which vibrates at a certain frequency, used as a very accurate clock signal for computer or other high precision timing applications


  • A homogeneous solid material with geometrically arranged outer surfaces, and a symmetrical internal structure. Crystals may be composed of atoms, molecules, or ions, and each has specific properties, such as index of refraction, hardness, and a unique crystal lattice. The applications of crystals in electronics are many, including their use in lasers, semiconductors, and in miniaturized components.
  • A specific crystal fragment, such as quartz crystal, a piezoelectric crystal, or semiconductor crystal.


  • noun a chemical formation of hard regular-shaped solids


  • noun an amphetamine, or cocaine. An item of drug users’ jargon.

Origin & History of “crystal”

The prehistoric Indo-European base *kru- produced several words denoting ‘hard outer surface’, including English crust, Old high German hrosa ‘crust’, and Old Norse hrúthr ‘crust’. In some cases they reflect a hardening caused by freezing: Old High German hrosa, e.g., also meant ‘ice’, and Greek krúos meant ‘frost’. from this was derived krustaímein ‘freeze’, which in turn formed the basis of krústallos ‘ice’. when Old English first acquired the word, via Latin crystallum and Old French cristal, it still meant ‘ice’, a sense which survived until the 16th century, although losing ground all the time to the metaphorical extension ‘clear mineral’.