A relation is a connection or link between two or more things. When scientists study the relation between exercise and health, they're examining how one affects the other. When you notice a relation between studying and test scores, you've spotted how they connect.

Relations can be logical, like the relation between clouds and rain, or mathematical, like the relation between the numbers 4 and 8 (one is double the other). In science, discovering relations helps us understand how the world works: Newton discovered the relation between force, mass, and acceleration.

The word also describes connections between people. Your relations are your family members: aunts, uncles, cousins, and grandparents. When you visit relations during holidays, you're seeing family. People also talk about the relations between individuals or groups: the relation between two friends, or international relations between countries.

You might also hear about public relations, which means managing how people perceive a company or organization, or in relation to, meaning compared with something else. If someone says you're tall in relation to your classmates, they mean compared to them.

The word relationship means almost the same thing, but it often emphasizes the quality or nature of the connection, like a close relationship between siblings or a cause-and-effect relationship between variables.