'ancestral' ultimately comes from the noun 'ancestor' plus the adjectival suffix '-al'. 'Ancestor' entered English from Old French 'ancestre', which in turn came from Latin 'antecessor' (from 'ante-' meaning 'before' and 'cedere' meaning 'to go').

'ancestor' was borrowed into Middle English from Old French 'ancestre' (or Medieval Latin 'ancestralis' for adjectival forms). The modern English adjective 'ancestral' developed by combining the base noun with the suffix '-al' to mean 'of or relating to ancestors'.

Originally referring simply to a person who went before ('ancestor'), the derived adjective came to mean 'related to or inherited from those ancestors' and is now used broadly for lineage, inherited traits, and traditional properties.