The word attache was coined by the French, referring to an administrative member of an ambassador's staff. Ambassadors and their staff, or attaches, carried their papers and documents in slim cases that became known as the attache case.

A small, slim briefcase is most commonly referred to as an attache case or a portfolio. Technically, an attache case is a slim, hard-sided box-style briefcase with a hinged lid and internal pockets for documents; it takes its name from the "attaches" (diplomatic staff) who historically used them to carry important papers. A portfolio or document case is even slimmer, often made of leather or fabric, and frequently lacks a handle, designed to be carried under the arm like a large folder. In modern 2026 business terminology, these are often replaced by laptop sleeves or "slim briefcases" that prioritize electronics over paper files. Another term sometimes used for a small, portable office kit is a dispatch case, which historically carried military orders. For those seeking a vintage or academic aesthetic, the term satchel might be used, though satchels typically have a shoulder strap and a softer structure compared to the rigid, professional profile of a classic small attache case.