[1] A rectangular cuboid is a convex polyhedron with six rectangle faces.

Rectangular cuboids may be referred to colloquially as "boxes" (after the physical object).

, then:[5] Rectangular cuboid shapes are often used for boxes, cupboards, rooms, buildings, containers, cabinets, books, sturdy computer chassis, printing devices, electronic calling touchscreen devices, washing and drying machines, etc.

The shape is fairly versatile in being able to contain multiple smaller rectangular cuboids, e.g. sugar cubes in a box, boxes in a cupboard, cupboards in a room, and rooms in a building.

A perfect cuboid is an Euler brick whose space diagonal is also an integer.

However, this number increases significantly to at least 54 for a rectangular cuboid of three different lengths.