Colossal means extraordinarily large, massive beyond what seems normal or reasonable. When something is colossal, it's so huge it makes you stop and stare, dwarfing everything around it.

A colossal building towers above everything around it. A colossal mistake is a blunder so huge it affects everything that follows. An elephant is large, but a blue whale is colossal, weighing as much as 25 elephants combined. When a student faces a colossal amount of homework, they're looking at a mountain of assignments that seems almost impossible to finish.

The word carries a sense of awe or sometimes being overwhelmed. A colossal success means achievement beyond anyone's expectations. A colossal failure means disaster on a grand scale. Unlike words like “huge” or “enormous,” colossal suggests something almost unbelievable in its size or impact, something that changes how you see everything around it.