Grain holder is a term used to describe a container used to store grain. The most common solutions for this term are SACK, SILO, and BIN. A SACK is a large bag made of cloth, paper, or plastic that is used to store and transport grain. A SILO is a tall cylindrical structure made of concrete or metal that is used to store grain. A BIN is a large container made of wood, metal, or plastic that is used to store grain.