What's an Aggregate Root?

Question

I\'m trying to get my head around how to properly use the repository pattern. The central concept of an Aggregate Root keeps coming up. When searching both the web and Stack

Answer 1

From a broken link:

Within an Aggregate there is an Aggregate Root. The Aggregate Root is the parent Entity to all other Entities and Value Objects within the Aggregate.

A Repository operates upon an Aggregate Root.

More info can also be found here.