What is the term for the process of combining two or more sites under one ownership for greater utility and value?

The term that refers to the process of combining two or more sites under one ownership for greater utility and value is known as "Plottage." Plottage specifically addresses the increase in value that can result from combining adjacent parcels of land. When land is assembled into a single ownership, it can often yield a higher combined value than each parcel would have if sold separately, due to factors like enhanced development potential or better utilization of the space.

Assemblage is related but does not specifically emphasize the value increase that occurs from combining these properties. It covers the action of bringing together multiple parcels under a single ownership but does not quantify the resulting enhancements in value. Consolidation may also relate to bringing together properties or efforts but does not specifically encompass the context of real estate in a way that highlights the value increase. Integration is a broader term that might apply to many fields, including economics and business, but it does not specifically denote the combination of properties as it pertains to real estate.

In summary, "Plottage" accurately captures the essence of both the act of combining properties and the resulting increase in value, making it the correct answer in this scenario.