The term 'TANK UNIT' can be broken down into two crossword solutions: GALLON (6 letters) and ARMOREDDIVISION (15 letters). A gallon is a unit of measurement for liquid volume, equal to four quarts or eight pints. An armored division is a type of military unit that is equipped with tanks and other armored vehicles. This type of unit is typically used in combat situations and is designed to provide protection and mobility on the battlefield.