Tremendous means extraordinarily large, powerful, or impressive. When something is tremendous, it goes far beyond ordinary in size, force, or impact.

A tremendous earthquake shakes buildings and changes landscapes. A tremendous storm brings powerful winds and heavy rain. A tremendous crowd fills every seat in a stadium and spills into the aisles. The word captures that sense of wow, that's huge or that's really powerful.

The word also describes achievements or efforts that inspire awe. A scientist makes a tremendous discovery that changes how we understand the universe. An athlete shows tremendous skill in winning a championship. A student puts in a tremendous amount of effort to master a difficult subject.

Notice that tremendous usually carries a positive feeling, even when describing something powerful or large. We say someone faced a tremendous challenge, meaning it was difficult but impressive to overcome. We rarely use tremendous for things that are simply bad without any element of being remarkable or important.