This is the 16702nd most frequent Russian word.
сквозной
"Skvoznoi" means "through, thorough, or all-encompassing."
In this context, 'сквозной' means 'through' or 'connecting', referring to a passage that goes entirely through something.
У нас был сквозной проход через парк.
We had a through passage through the park.
Here, 'сквозной' is used to describe a storyline that runs throughout or connects parts of a narrative.
Идея сквозного сюжета объединила все главы книги.
The idea of a through storyline connected all chapters of the book.
In this usage, 'сквозной' pertains to something open or continuous to allow passage, often for air or light.