How do I can find file system(like `/etc`) in `man` command

Question

I want to know what is the role of etc in man command.

but, does not find etc in man.

$ man etc
No manual entry for etc

I am using CentOS. The details are below

$ cat /etc/centos-release
CentOS Linux release 7.3.1611 (Core)

Thank you for reading!