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

→ Welsh cywir (mention)
→ Irish contúirt (mention)
→ Irish cóir (mention)
→ Galician cómaro (derived)
→ Old Irish co (inherited)
→ Old Irish cóir (mention)