Examples: cartography card archaeology archetype monarchy legal loyal purse personal cinema kinase car carpenter hippopotamus Mesopotamia dative data date
...
Proto-Celtic *towissākos

→ English taoiseach (mention)
→ Welsh tywysog (inherited)
→ Irish Taoiseach (inherited)
→ Irish taoiseach (inherited)
→ Irish tosach (inherited)
→ Old Irish tosach (inherited)
→ Old Irish toísech (inherited)