ANSI coded lamps (American National Standards Institute) use completely arbitrary codes, and the letters really mean nothing. I don't believe they ever began with 'A', but begin with B-F, and a few G's have come about in latter years. (and you never find the letter Q in the code)(and 'HPL' is not an ANSI code)
'F' doesn't indicate Ferrule, since that would also include the single-ended FEL 1kw lamp (G9.5 base) as well as the FAD, FDN, FCM, etc double-ended lamps.
With luck, the 1k PAR64's are alphabetical by beam spread (FFN, FFP, FFR, FFS), but that is about it.
The FAY lamp, by pure luck, has 3 letters that are pronouncable in a single syllable.
The LIF codes used for most lamps in the industry in Europe are a combination of letters and numbers, and again don't really mean anything.