See Also: Attack Surface
Physical Attack Surface Area comprises all endpoint devices that an attacker can gain physical access to, such as desktop computers, hard drives, laptops, mobile phones, and Universal Serial Bus (USB) drives. The physical attack threat surface includes carelessly discarded hardware that contains user data and login credentials, users writing passwords on paper, and physical break-ins.
Organizations can protect the physical attack surface through access control and surveillance around their physical locations. They also must implement and test disaster recovery procedures and policies.
Source: https://www.fortinet.com/resources/cyberglossary/attack-surface