Does any one know what the "c" stands for when setting file permissions?

example...

when you ls -l, it displays the permissions on that file like this
-rw-rw-rw- 1 root root 13666 Apr 11 00:37 filename

now i know the - is for a file and "d" is for a directory but what does the "c" stand for?

I cant find it any where, does anyone know?