In Magento, each store has its own root category. The root category acts as the top-level category under which all other categories and products are organized for that particular store. This structure allows for different catalog structures across multiple stores within a Magento installation, enabling a tailored product offering and navigation experience for each store. The ability to assign a unique root category to each store is a fundamental aspect of Magento's multi-store functionality, providing the flexibility to cater to diverse market segments or branding requirements.