Windows Server 2003 Question:

A DHCP scope is a valid range of IP addresses which are available for assignments or lease to client computers on a particular subnet. In a DHCP server, you configure a scope to determine the address pool of ip which the server can provide to DHCP clients.

Scopes determine which IP addresses are provided to the clients. Scopes should be defined and activated before DHCP clients use the DHCP server for its dynamic IP configuration. You can configure as many scopes on a DHCP server as is required in your network environment