enclosed

This term is primarily used in professional correspondence and architectural descriptions. In a business context, it refers specifically to items sent within the same envelope as a letter, serving as a formal signal to the recipient to look for additional documents. It is more formal than saying "included" or "attached," the latter of which is now more common in digital email communication.

When describing physical spaces, the word emphasizes a sense of containment or protection. It suggests a boundary that separates an interior area from the exterior, often implying security, privacy, or shelter from the elements. This distinguishes it from "closed," which refers to the state of an opening, whereas "enclosed" refers to the state of being surrounded.