A cuboid is a three-dimensional geometric shape with six rectangular faces. Each face meets at right angles, and opposite faces are equal in size. The dimensions of a cuboid are defined by its length, width, and height, making it a versatile shape found in everyday objects like boxes and buildings. Cuboids are also known as rectangular prisms. They can be classified based on their dimensions; for example, a cube is a special type of cuboid where all sides are equal. Understanding cuboids is essential in fields like mathematics, architecture, and engineering, where spatial reasoning is important.