The return movement of a means of transport providing a transport service in one direction.

Backfeeding is the flow of electric power in the direction reverse to that of the generally understood or typical flow of power.

The removal of weld metal and base metal from the weld root side of a welded joint to facilitate complete fusion and complete joint penetration upon subsequent welding from that side.

Background radiation is a measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources.

A material or device placed against the backside of the joint, or at both sides of a weld in electroslag and electrogas welding, to support and retain molten weld metal.

A weld pass made for a backing weld

Backing in the form of a ring, generally used in the welding pipe.

The pressure existing on the exhaust side of a system, e.g. the pressure opposing the motion of an engine piston during its exhaust stroke.

Any individual, generally an officer, who has been designated by the vessel master to be on call if assistance is needed on the bridge.

Backward erosion often occurs in non-plastic soils such as fine sands. It can occur in sandy foundations, within the dam or levee, or in cofferdams under high flood pressures during construction, causing unravelling at the downstream face.

A plate used to direct fluid flow, e.g. the hot gases in a boiler furnace or the oil in a sump tank.

Bagasse is the dry pulpy fibrous material that remains after crushing sugarcane or sorghum stalks to extract their juice.

Various kinds of commodities usually packed in sacks or in bags, such as sugar, cement, milk powder, onion, grain, flour, etc.

The Baghdad Battery or Parthian Battery is a set of three artifacts which were found together: a ceramic pot, a tube of copper, and a rod of iron.

The balance of system encompasses all components of a photovoltaic system other than the photovoltaic panels. This includes wiring, switches, a mounting system, one or many solar inverters, a battery bank and battery charger.

The outdoor air temperatures where internal heat gains from people, appliances, etc. offset the envelope heat loss to the atmosphere.

The ratio, of the blade area situated forward of the rudderstock to the total rudder blade area.

The cubic capacity of a cargo hold measured to the inside of the frames or cargo battens.

A ball valve is a form of quarter-turn valve which uses a hollow, perforated and pivoting ball to control flow through it.

Any solid or liquid weight placed in a ship to increase the draught, to change the trim, or to regulate the stability. Ballast water is allocated during the voyage to accommodate changes in the distribution of cargo and consumables...