An eyewitness is someone who personally sees an event happen and can tell others what they observed. If you watch a car accidentally back into a mailbox, you're an eyewitness to that accident. If you see your friend score the winning goal in soccer, you're an eyewitness to that moment.

The word combines “eye” (what you see with) and “witness” (someone who observes something). Eyewitnesses play an important role in our justice system because they can describe what happened during a crime or accident. Police officers often interview eyewitnesses to understand what occurred.

However, eyewitness accounts aren't perfect. Two people watching the same event might remember different details or describe things differently. Memory can be tricky: if you witness something surprising or frightening, you might remember certain parts vividly but miss other details entirely. Scientists who study memory have found that eyewitnesses sometimes fill in gaps without realizing it, or their memories can change over time.

That's why investigators usually seek multiple eyewitnesses and look for other evidence, like video footage or physical clues, to confirm what happened. Still, being an eyewitness means you have firsthand knowledge that others don't have, which makes your perspective valuable.