Briefcases and attaches are typically thin, narrow box-shaped bags or cases traditionally used for professional purposes, like carrying files and documents to client meetings. Many briefcases and attaches have a rigid frame and feature handles for easy carrying. They both got their names from the people who first used them—lawyers carried their court briefs in protected cases, and diplomatic or cultural attaches traveled with important documents and papers safe in their bags.
Traditionally, there was a subtle size difference between briefcases and attaches, however the two terms have come to be used interchangeably.