ביזוין
'Bieżuń (town in central Poland)'

ETYMOLOGY

{The Yiddish name was probably influenced by the pronunciation of the word בזיון.}
Beider argues that the vowel was diphthongized due to "anticipatory softening" before a palatalized consonant. The Polish etymon was from a dialect variant in which the /u/ has lowered to /o/ before a nasal.
Polish Bieżuń.

BIZOy'N {Yiddishland, Paul Glasser}