Glass composed of at least two different layers, generally one of transparent glass and one of opal, opalescent or coloured glass.
Note: In lighthouse practice, the use of flashed glass is confined to coloured glass.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
Celsius (previously Centigrade)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM