(/ˌnɒm də ˈpluːm/)
1. A pen name or pseudonym
… In 1887, he self-published his “Unua Libro,” or “First Book,” a primer on the proposed language, with explanatory materials in Russian. It contained a pronunciation guide, a dictionary, and a grammar, plus translations of the Lord’s Prayer, an excerpt from the Hebrew Bible, a poem by Heine, and other items. He called the language the lingvo internacia, but people soon began referring to it as Esperanto, after the nom de plume that he had given himself as the book’s author, Doktoro Esperanto (Doctor Hopeful).