This is the 3575th most frequent Russian word.
склад
Warehouse.
The word 'склад' is used here as a noun meaning 'warehouse' or 'storage facility', describing a building used for storing goods.
Этот склад хранит множество товаров.
This warehouse stores many goods.
The word 'склад' is used metaphorically to describe the organization or type of someone's mindset, often referring to 'type' or 'characteristic'.
У него склад ума математический.
He has a mathematical type of mind.
Here, 'склад' refers to the composition, structure, or format of something, in this case, a book.