The Latin word atavus
Word atavus
Meaning great grandfather, ancestor

Other words that might be of interest
levir ‘brother in law’, avus ‘grandfather’, fēmina ‘woman’, vir ‘man’, homō ‘man, human being’, puer ‘child’, uxor ‘wife’, mulier ‘wife’, maritus ‘husband’, māter ‘mother’, pāter ‘father’, abbas ‘father’, glōs ‘sister in law’, nepōs ‘grandson, nephew’