Apache/.htaccess

About
.htaccess is a filename used by the Apache web server for certain types of configuration. In a multi-user (i.e. shared) web hosting environment, the main Apache configuration files are usually not writable by the user, but .htaccess files live within the public html directory structure (i.e. within the area where a webmaster would need to be able to have full read/write access) and may be created as needed.

Reference

 * Apache Tutorial: .htaccess files