A discovery is finding or learning something that was unknown before. When you search through your closet and find a toy you'd forgotten about, that's a discovery. When scientists figure out a new planet orbiting a distant star, that's a discovery too.

The word works on many levels. A detective makes discoveries while investigating a case, piecing together clues to reveal the truth. An archaeologist makes discoveries by unearthing ancient cities buried under centuries of soil. A student might make a discovery while reading, suddenly understanding how photosynthesis works or why the American Revolution happened.

Some discoveries change everything. When Alexander Fleming discovered penicillin in 1928, he found a substance that could kill bacteria and save millions of lives. When European explorers reached continents unknown to them, they connected civilizations that had never known each other existed. But smaller discoveries matter too: discovering that you love playing chess, discovering a shortcut to school, or discovering that your best friend shares your sense of humor.

The word can also mean the act of discovering itself. Historians talk about “the Age of Discovery” when European explorers mapped unknown oceans. Lawyers use discovery to describe the process of gathering evidence before a trial.

What makes something a true discovery is that element of revealing what was hidden, unknown, or unrecognized before.