Okay kiddo, have you ever seen the roof of a house? It's that thing that's above our heads when we're inside a room.
Now, if you take a closer look at the roof, you'll notice that it extends beyond the walls of the house to form a kind of overhang. This overhang is called an eave.
Eaves are important because they help prevent water from getting inside the house when it rains. The water from the rain hits the roof and slides down the slope of the roof, and then when it reaches the eaves, it drips off and falls to the ground.
Eaves also help to provide shade and protection from the sun. In hot weather, the eaves can keep some of the sunlight from entering the house through the windows, making the inside of the house cooler.
So there you have it, eaves are the part of the roof that hangs over the walls of the house and helps keep rain out and provide shade.