What term describes a private collection of LANs and WANs belonging to a single organization?

The term that best describes a private collection of LANs (Local Area Networks) and WANs (Wide Area Networks) belonging to a single organization is an intranet. An intranet functions as a private network, utilizing Internet protocol technology to share any part of an organization's information or operational systems within that organization. It is designed for the exclusive use of an organization's employees and can include various types of network resources, databases, and applications that are accessible only to those within that organization.

In contrast, an extranet refers to a controlled private network that allows access to outside users (like partners or vendors) while still being part of an organization's internal network. The Internet refers to the vast public network that connects millions of private, public, academic, business, and government networks. A VPN (Virtual Private Network) provides a secure connection over the Internet, allowing remote users to connect to the organization's network, but it is not a collection of networks in itself. Thus, the term intranet specifically captures the essence of a private, internal collection of networks for a single organization.