Silo: It’s a word that comes from Greek and means pit or hole to keep or store “grain” or other bulk materials such as clay. Initially, it was a dark and large space with a roof so the weather could not spoil the clay. There are many different types of buildings designed for storing materials. Three types of silos are in widespread use today: bunker silos, bag silos and tower silos, which is the most common and can be square or cylindrical. They are made of different materials such as wood, concrete or metal (aluminum or steel).