Diffraction and interference are known to be two terms that are normally used in Science. Some people assume that diffraction is a type of interference, but this is not true at all. Diffraction occurs when there is a wave of light that will pass through an opening.
The light will have a tendency to spread out. Interference is known to be something that will happen. The waves meet up, and there are different waves that may overlap with each other. There are instances when diffraction without interference can occur. Take note that there are different types of diffraction that you should know so that you can understand how this works better.