A steam box is a long, sealed container used to steam wooden planks for the purpose of making them easier to bend. Once fastened or clamped into the desired position and left to dry, the wood will hold the new shape. Steam boxes allow for much more efficient use of wood. Instead of cutting the desired shape away from a large and more expensive piece of wood and leaving much scrap to be discarded, steam boxes allow for a smaller piece to be bent in the general shape and leaving much less scrap. Steam boxes also allow the wood to bend beyond its dry breaking point, which is useful in making extreme curves with the wood. In many cases, the bent piece is stronger than an identical piece cut from larger stock. Steam bending wood allows the wood grain to follow the bend, leaving it strong where a piece cut from larger stock would snap across crosscut grains or laminated joints.

The largest steam boxes are used in shipbuilding to bend the large planks for the frame and hull. However, smaller ones are used in making a variety of consumer items, such as rocking chairs, other furniture and even walking canes.

Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air. At lower pressures, such as in the upper atmosphere or at the top of high mountains water boils at a lower temperature than the nominal 100 °C (212 °F) at standard temperature and pressure. If heated further it becomes superheated steam.

The enthalpy of vaporization is the energy required to turn water into the gaseous form when it increases in volume by 1,600 times at standard temperature and pressure; this change in volume can be converted into mechanical work by steam engines and steam turbines. Steam engines played a central role to the Industrial Revolution and modern steam turbines are used to generate electricity. If liquid water comes in contact with a very hot substance (such as lava, or molten metal) it can create a steam explosion. Steam explosions have been responsible for many foundry accidents and may also have been responsible for much of the damage to the plant in the Chernobyl accident.

Box (plural boxes) describes a variety of containers and receptacles for permanent use as storage, or for temporary use often for transporting contents. The word derives from the Greek πύξος (puxos), "box, boxwood".

Boxes may be made of durable materials such as wood or metal, or of corrugated fiberboard, paperboard, or other non-durable materials. The size may vary from very small (e.g., a matchbox) to the size of a large appliance. A corrugated box is a very common shipping container. When no specific shape is described, a box of rectangular cross-section with all sides flat may be expected, but a box may have a horizontal cross section that is square, elongated, round or oval; sloped or domed top surfaces, or non-vertical sides.

A decorative or storage box may be opened by raising, pulling, sliding or removing the lid, which may be hinged and/or fastened by a catch, clasp, or lock.

Several types of boxes are used in packaging and storage.

Depending on locale and specific usage, the terms carton and box are sometimes used interchangeably.