An abnormality is something that differs from what's normal, usual, or expected. When a doctor examines an X-ray and spots an abnormality, they've found something that doesn't look like it should: maybe a bone has an unusual shape, or there's a shadow that shouldn't be there.

Scientists use the word when they discover something unexpected in their research. A meteorologist studying weather patterns might notice an abnormality in temperatures for December, with readings much higher or lower than usual for that time of year.

In everyday life, you might notice abnormalities too. If your normally energetic dog suddenly seems tired and won't eat, that behavioral abnormality suggests something might be wrong. If test scores come back with one abnormal result, it simply means that one measurement fell outside the typical range.

The word doesn't automatically mean something bad, just different from the standard or expected pattern. Sometimes abnormalities turn out to be harmless quirks. Other times they signal that something needs attention. Either way, noticing abnormalities helps us spot when things have changed from their normal state, which is often the first step in understanding what's going on.