This is a measure — usually a ratio or percentage — of how much radiation, or light, falling onto an object will be reflected off it. Usually, albedo refers to the amount of sunlight that an object bounces back into space. Light-colored objects — such as snow, fluffy clouds or white t-shirts — reflect a lot of sunlight, meaning they have a high albedo. Other substances — such as dark soil or water (which absorb sunlight well) — have a low albedo.
In a sentence
Extra thick clouds have a high albedo — so they might have a role to play in limiting the warming due to climate change.