Differences between Netid & hostid, Subnettin & Supe

Is it possible if you could explain to me the differences between of the following terms with examples:

(1) Netid and hostid.
(2) Subnetting and Supernetting.

1)

NET ID = identifier for your network
HOST ID = valid IP address for a host (so, not a BC address or NET ID)

2)

Check the subnetting part on this website. It's great.. really!

www.firewall.cx/ip-subnetting-intro.php