tumulus

UK: /ˈtjuːmjʊləs/ US: (to̅o̅′myə ləs, tyo̅o̅′-)

Inflections of 'tumulus' (n):

tumuluses

npl

tumuli

npl

WordReference Random House Unabridged Dictionary of American English © 2025

tu•mu•lus  (to̅o̅′myə ləs, tyo̅o̅′-), n., pl. -lus•es, -li 

(-lī′). 
1. [Archaeol.] an artificial mound, esp. over a grave;
   barrow.
2. Geology a domelike swelling or mound formed in congealed lava.

• Latin: mound, swelling, equivalent. to tum(ēre) to swell + -ulus -ule
• 1680–90

Collins Concise English Dictionary © HarperCollins Publishers::

tumulus / ˈtjuːmjʊləs/ noun ( -li / -liː/)

1. (no longer in technical usage) another word for barrow2

Etymology: 17th Century: from Latin: a hillock, from tumēre to swell up