Wikidata is a free and open knowledge base that acts as a central repository for structured data. It supports various Wikimedia projects, such as Wikipedia, by providing a common source of information that can be easily accessed and edited by users worldwide. The data in Wikidata is organized into items, each identified by a unique identifier. Users can add, modify, and query this data, making it a collaborative platform for sharing knowledge across different languages and cultures. This allows for more consistent and reliable information across various online resources.