About this term
Source: Oxford University Press
Vitreous or glass paste used in a variety of ways to decorate a metal or, more rarely, ceramic surface. The word ‘enamel’ is of obscure origin. It probably derives from smelzan (Old High Ger.: ‘to smelt’) and esmail (Old Fr.). The Greek philosopher Philostratos Lemnios wrote that ‘barbarians…pour these colours into bronze moulds, so that the colours become hard as stone’ (Imagines I. xxviii); the ‘colour’ probably refers to molten glass. This may have been a description of a process which was not enamelling but its precursor. The art of enamelling was a logical progression in the artistic alliance between the goldsmith and the glassworker. During the 15th century BC in Egypt coloured, cut-glass pieces were decoratively embedded into gold cloisons (cells); the inclusion of molten glass may have been a later refinement of the Greeks and the Celts.
From Grove Art Online