Interesting point about it being NCC, not N.C.C. Given that it is U.S.S., not USS. Maybe it’s an alien word or name — the name of the individual who came up with the numbering system? Mr. T’. O. NCC.
Or it could be an abbreviation anyway, in which case I like:
United (Federation of Planets)
Star(fleet)
(Star)ship
…to fit with canon,
…and maybe something like:
Nikopoulos, ch’Thane, & Carrgh
…the Human, Andorian, and Tellarite who came up with the numbering system or who were the first triumvirate in charge of doing so.