What term describes designating islands of extreme security within a sea of moderate security?

The term that best describes designating islands of extreme security within a sea of moderate security is "Enclaving." Enclaving refers to creating specific areas or zones that have heightened security measures compared to surrounding areas. This concept is useful in physical security planning as it allows for the protection of sensitive assets or critical operations while still maintaining a functional environment around them.

By implementing a strategy of enclaving, organizations can effectively control access to high-security areas, reduce potential threats, and manage risk without imposing excessive security measures across the entire facility. This approach also aids in resource allocation, ensuring that security personnel and technology are focused where they are most needed, thus optimizing the overall security posture.

Other terms, while related to security measures, do not specifically address this concept of creating secure "islands" within a broader area of varied security levels. For instance, fortification typically involves strengthening a structure against attacks, segmentation refers to dividing an area into smaller parts for security purposes, and zoning usually pertains to categorizing different areas according to specific security requirements rather than the juxtaposition of high and moderate security areas.