The phrase "huge reservoir" means a very large storage area or container for holding and storing a large amount of something, like water or energy. Full definition
[Translate] By Paul Brown, Climate News Network Dams create huge reservoirs for hydropower plants in Norway. (globalpossibilities.org)
By doing so, the two scientists found a unique population of galaxies hosting huge reservoirs of hydrogen gas, the fuel for forming new stars like our Sun. (sciencedaily.com)
«We were hoping to see huge reservoirs,» says Lunine, «because that» swhat you need to maintain methane in the atmosphere for billions ofyears.» (discovermagazine.com)