Untold means too numerous, vast, or great to be counted or fully described. When a scientist makes a discovery that saves untold lives, she helps so many people that no one could calculate the exact number. When an inventor's work brings untold benefits to society, the positive effects spread so widely and deeply that you couldn't list them all.

The word captures something almost unimaginable in its scale. A library fire might destroy untold treasures of knowledge. A breakthrough in medicine might prevent untold suffering. The word suggests an amount so large it overwhelms our ability to measure it.

Untold can also mean a story that hasn't been shared or revealed yet. The untold story of an explorer's journey might contain adventures no one has heard about. Sometimes history books focus on famous leaders, leaving the untold stories of ordinary people who also shaped events. When someone finally shares these hidden accounts, they're telling the untold story.