1. A flat briefcase for keeping loose sheets of paper, prints, drawings, maps, music, photographs, etc.: Some artists present portfolios of their work to people who might be willing to buy or to exhibit their artwork.
2. Investments that are owned by someone or an organization: The investment manager spent some time discussing Janet's retirement portfolio with her.

In the phrase, "without portfolio" when referring to a government minister, it means that he is not in charge of a specific department of state; or, in other words, he is a "Minister without Portfolio".
3. Etymology, from Italian portafoglio, "a case for carrying loose papers"; from porta, portare, "to carry" + foglio, "sheet, leaf," from Latin folio, folium, "leaf".