A .htaccess file is a granular configuration file for the Apache web server software, used to set or alter the server's configuration settings for the directory in which it is present, and/or its child directories.
WordPress uses an .htaccess file in conjunction with the mod_rewrite Apache module to produce permalinks.
Note that . htaccess is a hidden file in Unix/Linux (as dictated by the preceding period '.'), meaning it may not be visible using the default settings of some FTP clients.
- See also: chmod
- Related articles: htaccess for subdirectories, Using Permalinks, UNIX Shell Skills, Changing File Permissions
Reference https://codex.wordpress.org/Glossary
