tumulus
Concise Oxford English Dictionary © 2008 Oxford University Press:
tumulus /ˈtjuːmjʊləs/
▶noun (pl. tumuli /-lʌɪ, -liː/) an ancient burial mound; a barrow.
– origin ME: from L.; rel. to tumere ‘to swell’.
'tumulus' also found in these Oxford entries:

