HBase is an open-source, distributed database built on top of the Hadoop ecosystem. It is designed to handle large amounts of structured data across many servers, providing real-time read and write access. HBase is modeled after Google's Bigtable and is suitable for applications that require quick access to vast datasets. One of the key features of HBase is its ability to scale horizontally, meaning you can add more servers to increase capacity and performance. It stores data in a column-oriented format, which allows for efficient storage and retrieval, making it ideal for big data applications and analytics.