This word was mentioned by Adrian Belew in an October 1981 interview, as an example of what he could hear from Robert Fripp, when asking for some inspirational words to write lyrics. Although this word didn't inspire Adrian to write a song, it did inspire me to try to find out what it might mean. Here is what I came up with:
nomic (Greek) - norm, law
denomic ~ normalized (similar to denominated)
alged - probably stands for allegedly, so inalged would mean "inallegedly", something one could not even suppose.
In that way, inalgedenomic means something, which even supposedly cannot be normalized or categorized. Quite characteristic of King Crimson, isn't it?