From Longman Dictionary of Contemporary Englishtumulustu‧mu‧lus /ˈtjuːmjələs $ ˈtuː-/ noun (plural tumuli /-laɪ, -li/) [countable] MXa very large pile of earth put over a grave by people in the past
Examples from the Corpus
tumulus• Already the pines on a distant tumulus away to the right were melting into one indistinguishable mass.• Later tombs here have no tumulus above but consist of a single large room cut into the stone. 