From MEPIS Documentation Wiki
The /etc directory tree contains configuration files for the system, such as the inittab and fstab files which are used at boot time to set the target runlevel and to specify mount points for additional filesystems. As a result, /etc cannot be a separate filesystem - instead it must be a directory within the root filesystem.
The /etc directory is where many of the main configuration files are stored. With the proper permissions most of these files can be edited by hand using your favorite text editor. One example of an /etc configuration file is /etc/fstab. This file is where "mount points" are defined. Mount points are where an "in between" sort of directory is created and used to access some of the drives from the /dev directory. more detail