pseudonym UK /ˈs(j)uː.də(ʊ).nɪm/US /ˈsu.də.nɪm/ noun1 •A fictitious name (more literally, a false name), as those used by writers and movie stars.The Reverend Charles Lutwidge Dodgson wrote "Alice's Adventures in Wonderland" under the pseudonym Lewis Carroll. formspseudonyms