To corroborate means to confirm or support a statement with additional evidence or testimony. When you corroborate something, you're backing it up with proof that shows it's true.

Imagine a student tells the principal she saw another student break a window. If two more students come forward and say they saw the same thing, their accounts corroborate her story. They're providing independent confirmation that makes the original claim more believable. Police investigators look for corroborating evidence like fingerprints or video footage that supports a witness's account of what happened.

The word suggests adding strength to something that might otherwise stand alone. One person's claim can be doubted, but when multiple sources or pieces of evidence point to the same conclusion, they corroborate one another. Scientists corroborate their findings by repeating experiments. Historians corroborate ancient stories by finding archaeological evidence that matches the tales.

Notice that corroborate doesn't mean merely agreeing with someone. It means providing actual evidence or testimony that backs up what they said. If your friend says she finished her homework and you say “I believe you,” that's not corroboration. But if you say “I saw her working on it in the library,” now you've corroborated her claim with firsthand evidence.