Horizontal partitioning is a database design technique where a table is divided into smaller, more manageable pieces called partitions. Each partition contains a subset of the rows from the original table, based on a specific criterion, such as a range of values or a specific attribute. This approach helps improve performance and manageability, especially for large datasets. By using horizontal partitioning, queries can be executed more efficiently since they can target specific partitions rather than scanning the entire table. This method is particularly useful in systems that handle large volumes of data, such as data warehouses or transactional databases.