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

→ Bulgarian перо (inherited)
→ Polish pierzyna (mention)
→ Russian птица (mention)
→ Russian перо (inherited)
→ Rusyn перо (inherited)
→ Silesian piōro (inherited)