We propose a file naming scheme, which we call HK (Hierarchical-Keyword-based) naming. In file systems, hierarchical naming has been used for these several decades. As the number of files stored in file systems increases, the weakness of hierarchical naming is getting recognized. Some researchers have proposed hybrid naming schemes which introduce attribute-based naming into hierarchical naming. However, they are unsatisfactory or too complicated. HK naming is the hybrid naming scheme that integrates hierarchical naming and attribute-based naming in a simple way. In HK naming, a file is named by a set of keywords and keywords are organized hierarchically. We illustrate the usefulness of HK naming by showing that HK naming can solve some problems in practical usage of file systems.