Old Church Slavonic плѣнъ

← Proto-Slavic *pelnъ (inherited)

→ Old Church Slavonic плѣньникъ (suffix)

→ Icelandic falur (cognate)

→ Latvian pelnīt (cognate)

→ Romanian plean (borrowed)

→ Russian плен (borrowed)

→ Russian полон (cognate)