Sequential access refers to a method of accessing data where information is read or written in a specific order, one piece after another. This means that to reach a particular item, you must go through all preceding items in the sequence. This method is commonly used in devices like tape drives and certain types of databases. In contrast to random access, where data can be retrieved in any order, sequential access can be slower for large datasets. However, it is often more efficient for tasks that involve processing large volumes of data in a linear fashion, such as streaming media or batch processing.