What term describes the large, towering cloud associated with thunderstorms?

The term that describes the large, towering cloud associated with thunderstorms is "Cumulonimbus." This type of cloud is characterized by its impressive vertical development, reaching heights of up to 12 kilometers (around 7 miles) into the atmosphere and often forming an anvil-shaped top. Cumulonimbus clouds are not only associated with thunderstorms but also produce heavy rain, lightning, tornadoes, and hail due to their strong updrafts and moisture content.

In contrast, cumulus clouds are generally puffy and indicate fair weather, stratus clouds are flat and featureless, often covering the sky in a uniform layer associated with overcast conditions, and cirrus clouds are high-altitude wispy clouds that typically indicate good weather but can suggest a change in the weather pattern. These characteristics highlight the unique role of cumulonimbus clouds in severe weather events, making them the correct answer for the question related to thunderstorms.