A sucker rod is a steel rod, typically between 25 and 30 feet (7 to 9 meters) in length, and threaded at both ends, used in the oil industry to join together the surface and downhole components of a reciprocating piston pump installed in an oil well.

Voltages below 110kV are considered to be subtransmission level voltages.

Substitute natural gas, or synthetic natural gas, is a fuel gas (predominantly methane, CH4) that can be produced from fossil fuels.

Substation automation refers to using data from Intelligent electronic devices (IED), control and automation capabilities within the substation, and control commands from remote users to control power-system devices.

Subsidence is the sudden sinking or gradual downward settling of the ground's surface with little or no horizontal motion.

Subsea Production Systems are typical wells located on the seabed, shallow or deep water.

Oil and gas fields reside beneath many inland waters and offshore areas around the world, and in the oil and gas industry the term subsea relates to the exploration, drilling and development of oil and gas fields in these underwater locations.

A submersible pump is a device which has a hermetically sealed motor close-coupled to the pump body.

A power transmission cable used carrying electricity, usually laid on the sea floor.

Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state

Subcritical steam – up to 705 °F (374 °C) and 3,208 psi (221.2 bar) (the critical point of water)

The sub-Arctic climate (also called subpolar climate, or boreal climate) is a climate characterised by long, usually very cold winters, and short, cool summers.

Sub-bituminous coal is a type of lower grade coal which contains 35%-45% carbon.

A stuffing box or gland package is an assembly which is used to house a gland seal. It is used to prevent leakage of fluid, such as water or steam, between sliding or turning parts of machine elements.

Student Energy is a global youth led organisation empowering the next generation of leaders to accelerate the transition to a sustainable, equitable energy future.

The internal structure of Earth, structure of the solid Earth, or simply structure of Earth refers to concentric spherical layers subdividing the Solid earth.

A fire retardant is a substance that is used to slow down or stop the spread of fire or reduce its intensity.

The fire point of a fuel is the lowest temperature at which the vapour of that fuel will continue to burn for at least five seconds after ignition by an open flame of standard dimension.

Photographic film used to measure exposure to ionizing radiation for purposes of personnel monitoring.

The magnetic field-producing component of an electrical machine.