陀 is a bound morpheme (语素) that rarely appears alone in modern Chinese. You'll most often encounter it as a phonetic component in transliterated words: 陀螺 (tuóluó, 'spinning top'), 佛陀 (Fótuó, 'Buddha'), and 陀思妥耶夫斯基 (Tuósītuōyēfūsījī, 'Dostoevsky'). Its classical meanings 'declivity' and 'steep bank' are now archaic and seldom used in everyday language.