Pin Cap (G.B.)
A cap (types F, G) which has one or more pins for fixing it in the lampholder.
Note 1: For particular numbers of pins, terms such as Three-Pin Cap are employed.
Note 2: In the U.S.A., a lamp having a cap with two pins is called a Bi-Post Lamp.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
centre of gravity
Celsius (previously Centigrade)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM