Aggregation means gathering separate things together into a collection or whole. When you collect baseball cards and keep them in a binder, that binder holds your aggregation of cards. When a website shows you the aggregated scores from all the baseball games played yesterday, it has gathered information from many different sources into one place.

Scientists use aggregation to describe how individual animals cluster together, like when starlings form those amazing swirling clouds in the sky. Data scientists talk about aggregating information, meaning they combine many small pieces of data to see bigger patterns.

Aggregation differs from simply piling things up randomly. It suggests purposeful collection with some organizing principle. A news aggregator doesn't just throw every article together; it collects news from multiple sources and organizes it so you can find what interests you. When researchers study aggregation, they're often interested in how and why separate things come together, whether that's data points, animal behavior, or particles in chemistry.