What is "fortochka"

n. A small ventilation window, spanning the frame of one window pane, that opens on hinges independently of the whole window, common in Russia, post-Soviet states and Finland.

A Fortochka is a small ventilation window. It usually spans the frame of one window pane and opens on hinges independently of the whole window. Fortochkas are in common use in Russia, other post-Soviet states ( Ukrainian: кватирка, kvatyrka), and Finland ( Finnish: tuuletusikkuna).

A fortochka can be used for ventilation during traditionally cold winters, when opening a whole window would be impractical for heat conservation purposes.