thumb|A window with a fortochka (in the upper left corner) A fortochka () is a small ventilation window generally not greater than 35x45 cm. 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 (, ), and Finland ().
thumb|A window with a fortochka (in the upper left corner) A fortochka () is a small ventilation window generally not greater than 35x45 cm. 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 (, ), and Finland ().
A fortochka can be used for ventilation during cold winters, when opening a whole window would be impractical for heat conservation purposes.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).