The compression ratio is the ratio between the volume of the cylinder and combustion chamber in an internal combustion engine at their maximum and minimum values.

Compressive strength or compression strength is the capacity of a material or structure to withstand loads tending to reduce size, as opposed to Tensile strength which withstands loads tending to elongate.

The central component of a heat pump system.

A compressor is a mechanical device that increases the pressure of a gas by reducing its volume.

A compressor stall is a local disruption of the airflow in the compressor of a gas turbine or turbocharger.

Computational fluid dynamics is a branch of fluid mechanics that uses numerical analysis and data structures to analyze and solve problems that involve fluid flows.

A technique using numerical methods and algorithms to solve and analyze problems that involves fluid flows.

Computer simulation is the process of mathematical modelling, performed on a computer, which is designed to predict the behaviour of, or the outcome of, a real-world or physical system.

A solar power system that utilises mirrors or lenses to concentrate sunlight onto a reciever where it can be converted into heat energy to drive a steam turbine.

In battery technology, a concentration cell is a limited form of a galvanic cell that has two equivalent half-cells of the same composition differing only in concentrations.

Concentrator photovoltaics is a photovoltaic technology that generates electricity from sunlight. Unlike conventional photovoltaic systems, it uses lenses or curved mirrors to focus sunlight onto small, highly efficient, multi-junction solar cells.

Condensation is the change of the physical state of matter from the gas phase into the liquid phase, and is the reverse of vaporization.

A heat exchanger in which hot, pressurized (gaseous) refrigerant is condensed by transferring heat to cooler surrounding air, water, or earth.

A voluntary system which gives a detailed assessment of the tanker present condition at the time of inspection. CAP is available to both charter-parties and owners.

Inspection of a vessel to determine its technical condition.

Condition monitoring is the process of monitoring a parameter of condition in machinery (vibration, temperature etc.), in order to identify a significant change which is indicative of a developing fault.

Normally a survey of limited scope and time, intended to identify any anticipated structural or corrosion-related deficiencies, and give an overall visual impression of the structural integrity.

Similar to firm service in that it is reserved and has priority over interruptible service.

Condition-based maintenance is maintenance when need arises. It is performed after one or more indicators show that equipment is going to fail or that equipment performance is deteriorating.

A conductive textile is a fabric which can conduct electricity.