When a developer combines two or more adjacent parcels of land into one large development, it is known as:

When a developer combines two or more adjacent parcels of land into a single, larger development, this process is referred to as assemblage. Assemblage allows for the larger piece of property to be utilized more effectively for development purposes, often enhancing its marketability and potential uses, whether for residential, commercial, or mixed-use projects.

This process is distinct from the other terms listed. Conformity refers to the principle that values of properties are greater when they conform to the surrounding properties in terms of style, use, and size. Partition, on the other hand, is the legal process of dividing a single parcel of land into separate pieces, which does not involve combining land. Lastly, subdivision pertains to the process of dividing a larger parcel of land into smaller lots, typically for the purpose of selling individual plots, which is the opposite of assemblage. Thus, the term assemblage precisely describes the act of combining properties for development, making it the correct choice.