Coherence (physics)

Coherence (in physics) means that all the parts of an object are connected and organized. Imagine a garden hose. If all the pieces of the hose are connected together so that the water that goes in one end comes out the other, we would say the hose is 'coherent'. This means each piece is connected to the others in the right way so that the water can flow smoothly from one end to the other.