People

sister

Source:*sestraProto-Slaviccertain

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English

sister

Polish

siostra

ˈɕɔstra

Cognate· distant (Indo-European)Same source — the sound laws connect them.

In all five languages

BCS script

Latin under Cyrillic

Russian
сестра́sestra
sʲɪˈstrainherited
Ukrainian
сестра́sestra
sɛˈstrainherited
Polish
siostra
ˈɕɔstrainherited
Polish turned e into o before a hard dental: sie- → sio-.
Czech
sestra
ˈsɛstrainherited
Bosnian-Croatian-Serbian
sestraсестра
ˈsestrainherited
English
sister
Distant English relative — Sister and *sestra go back to one Indo-European word.