The term 'Trunk Tool' is composed of two crossword solutions, 'JACK' and 'Tireiron'. A JACK is a mechanical device used to lift heavy objects, such as a car. It is usually operated by a crank or lever. A tireiron is a tool used to remove and replace tires on vehicles. It is usually a metal rod with a curved end that fits into the wheel rim. Together, these two tools are essential for any car trunk, allowing for the easy lifting and changing of tires.