thread

• Russian
  ни́ткаnitka

  ˈnʲitkəinherited

  The plain нить is bookish or figurative.

• Ukrainian
  ни́ткаnytka

  ˈnɪtkainherited
• Polish
  nić

  ɲitɕinherited

  Also the diminutive nitka.

• Czech
  nit

  ɲɪtinherited
• Bosnian-Croatian-Serbian
  konacконац

  ˈkonatsdifferent word · Proto-Slavic *konьcь 'end' (Russian коне́ц)
• English
  thread

Sound laws at work

• The fall of the yers