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

→ Czech pupek (inherited)
→ Polish pępek (inherited)
→ Russian пупок (inherited)
→ Serbo-Croatian пупак (inherited)
→ Serbo-Croatian pupak (inherited)
→ Slovak pupok (inherited)
→ Slovene popek (inherited)
→ Silesian pympek (inherited)
→ Old Czech pupek (inherited)