Symmetry breaking is sort of like when you take a group of things and split them into two different groups. It is like if you had a room full of people, and you wanted to create separate teams for a game. You could decide that everyone wearing a red shirt would be on one team, and everyone wearing a green shirt would be on the other team. By doing this, you have broken the symmetry of the whole group of people. It can also mean the same thing for some physical or mathematical things that have a particular pattern or shape, like a triangle. If you took the triangle and cut it in three different places, it would no longer be a triangle and would not look the same. This is an example of symmetry breaking.