The word 案件 is formed by combining two characters: 案, which originally means "table" or "desk" but by extension came to signify the official documents or records placed upon it, and 件, which means an item or a piece of something. Together, they create the concept of an "official document item" or a "recorded matter", evolving to specifically denote a formal case, typically a legal or criminal one, that is documented and requires investigation or judgment.