Tonne: The tonne, also known as the metric ton, is a unit of mass in the metric system. It is equal to 1,000 kilograms or 1,000,000 grams. It is widely used internationally for measuring larger quantities of mass and is equivalent to approximately 2,204.62 pounds.
A "slug," in the context of mass, is a unit of measurement primarily used in the United States customary and British imperial systems. It is not a widely used unit and is considered somewhat archaic. The slug is used to measure mass and is defined as the mass that accelerates at a rate of one foot per second squared (1 ft/s²) when a force of one pound-force (1 lbf) is applied to it. In other words, a slug is the mass that results in an acceleration of 1 ft/s² when a force of 1 lbf is applied to it.