Most learners first meet 鲁恩 in fantasy media: it's the standard Chinese rendering of English 'rune'. Also occurs as a personal name (Scandinavian Rune). The full term for the writing system is 鲁恩文字 (runic script).
Ancient Germanic / Norse alphabet (Futhark) used roughly 2nd–11th centuries — familiar to Chinese audiences from Vikings, Lord of the Rings, and ARPGs like Diablo and Path of Exile.