From Online Dictionary of Crystallography

Definition of crystal

Strange enough, the Online Dictionary of Crystallography lacks the entry "crystal".... I know it is a delicate affair, given the evolution the term is undergoing, to include not only aperiodic objects that diffract periodically but also two-dimensional crystals. Nevertheless, I think that an entry corresponding to the current official defintion by the Nomenclature Commission (if any) should exist. --MassimoNespolo 10:28, 25 January 2009 (UTC)