NEPTUNIAN Meaning of NEPTUNIAN in English Neptunian, n~ BrE AmE nep ˈtjuːn i‿ən ⇨-ˈtʃuːn- AmE -ˈtuːn- -ˈtjuːn- Longman Pronunciation English Dictionary. Английский словарь произношений Longman. 2012