To correlate means to have a connection or relationship where two things tend to change together in a predictable way. When scientists say that studying correlates with better test scores, they mean that students who study more usually get higher grades. The two things move together: more studying goes with higher scores, less studying goes with lower scores.

Correlation doesn't mean one thing causes the other, just that they're linked. Ice cream sales and drowning accidents correlate because both happen more in summer, but eating ice cream doesn't cause drowning. They're both connected to a third thing: warm weather.

You might notice correlations in everyday life. Playing more basketball might correlate with improved free throw accuracy. Reading more books might correlate with having a larger vocabulary. Getting enough sleep might correlate with feeling energetic at school.

As a noun, a correlation is the relationship itself. Scientists study correlations to find patterns in nature and human behavior. A strong correlation means two things are closely connected, while a weak correlation means they barely relate at all. Understanding correlations helps us spot patterns and make better predictions, even when we don't fully understand why things are connected.