The term 'capacity unit' can be broken down into three parts: CRAN (4 letters), TON (3 letters), and LITER (5 letters). CRAN stands for 'Cubic Feet per Minute, ' which is a unit of measurement for air flow. A TON is a unit of weight, equal to 2, 000 pounds. Finally, a LITER is a metric unit of volume, equal to 1, 000 cubic centimeters. Together, these three units form the term 'capacity unit, ' which is used to measure the capacity of a system or container.