The term FITTED ONE WITHIN ANOTHER can be summarized as 'nesting, ' which is the act of placing one object inside another. Nesting is a common practice in many areas, such as carpentry, where pieces of wood are fitted together to create a larger structure. It is also used in engineering, where components are placed within each other to form a single unit. In addition, nesting is often used in mathematics, where shapes or numbers are placed within each other to create a pattern.