When discussing Active Directory, what exactly is a domain?

What will be an ideal response?

A domain is a fundamental component or container that holds information about all network resources that are grouped within it--servers, printers, and other physical resources, users, and user groups. A domain usually is a higher-level representation of how a business, government, or school is organized, for example, reflecting a geographical location or major division of that organization. Every resource is called an object and is associated with a domain.