A cinder block is a rectangular concrete masonry unit made from a mixture of cement, water, and aggregates like coal cinders or ash. These blocks are lightweight, durable, and commonly used in construction for building walls, foundations, and other structures. They typically measure 16 inches long, 8 inches high, and 8 inches deep, but sizes can vary. Cinder blocks are often preferred for their fire-resistant properties and ease of handling. They can be stacked and mortared together to create strong, stable walls. Additionally, they can be painted or finished to enhance their appearance, making them versatile for both functional and aesthetic applications in construction.