Transmissivity (of an absorbing material)
The internal transmittance of a layer of the material such that the path of the radiation is of Unit: length, and under conditions in which the boundary of the material has no influence.
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