Horizontal fragmentation is a database design technique where a table's rows are divided into smaller, more manageable pieces called fragments. Each fragment contains a subset of the rows based on specific criteria, such as a range of values or a particular attribute. This approach helps improve performance and manageability by allowing queries to access only the relevant fragments instead of the entire table. This method is particularly useful in distributed databases, where fragments can be stored on different servers. By distributing data across multiple locations, horizontal fragmentation enhances data retrieval speed and reduces the load on any single server, leading to more efficient data management.