Which Azure Networking Component is The Core Unit

Virtual Networks is the core unit of Azure Networking Component.  With Virtual Networks  administrators can have full control over IP address assignments, name resolution, security settings, and routing rules. Azure VNets enable you to securely connect Azure VMs to each other and to extend your on-premises network to the Azure cloud. A VNet is a representation of your own network in the cloud and is a logical isolation of the Azure cloud dedicated to your subscription.