Complementary Wavelength (of a colour stimulus)
Wavelength of the monochromatic light stimulus that, when combined in suitable proportions with the colour stimulus considered, yields a match with the specified achromatic light stimulus.
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