All those words are more or less synonyms of each other, with only slight difference in meaning and they all work fine when describing Bitcoin. Cryptocurrency is more fitting cause it distinguises it to be a covert or encrypted means of transacting unlike Fiat which can be virtual or digital
In whitepaper, it is "A purely peer-to-peer version of electronic cash" but it is a long phrase.
You would shorten it to a "P2P electronic cash."