The Proto-Celtic word *tumbo-
Word *tumbo-
Meaning hill
Synonyms *brendo-

Other words that might be of interest
*kʷranno ‘tree’, *beljā ‘leaf, tree’, *arto ‘stone’, *gallo ‘stone’, *krako ‘stone’, *tela-mon ‘earth’, *ūrā- ‘earth’, *φī-wer-jō(n) ‘land, earth’, *brig ‘mountain’, *monjo- ‘mountain’