nested

This term describes a hierarchical arrangement where one item is contained within another of the same kind. In physical contexts, it emphasizes space-saving efficiency and a gradual reduction in size, such as with measuring cups or Russian dolls. It suggests a snug, interlocking fit that creates a compact unit.

In technical and computational contexts, the term refers to logical layering. A nested structure allows for complex conditional logic or data organization by placing one loop, function, or tag inside another. This creates a dependency where the inner element is subject to the constraints or scope of the outer element.