Network Segmentation is creating sub-networks within a corporate, enterprise, or another large network. Network segmentation allows for the containment of malware and other threats. This can also be very beneficial to the efficiency of a network’s performance. Network segmentation is a prescribed requirement for networks containing Payment Card Industry data (PCI). Network segmentation is an important cybersecurity protective measure that is usually part of any robust defense-in-depth cybersecurity program.
Source: Network Segment Definition