US gallon (gal)
Definition: US gallon na volume unit wey equal exactly 3.785411784 liters, or 4 US quarts.
History/origin: US gallon come from old English wine gallon wey United States keep after independence, instead of the later imperial gallon.
Current use: US gallons dey used for United States for gasoline, paint, industrial liquids, and bigger drink containers.
Cubic kilometer (km³)
Definition: Cubic kilometer na huge metric volume unit. One 1 km × 1 km × 1 km cube get 1,000,000,000 m³, or 1,000,000,000,000 L.
History/origin: Earth science need readable unit for very big natural volumes, so km³ help for water bodies, ice, rock, magma, and atmosphere-scale quantities.
Current use: km³ dey show for hydrology, climate reports, ocean volume estimates, glacier studies, volcanic eruption data, reservoir capacity, and large-scale geography.