The ability for an item to perform a required function under given conditions for a given time interval.
Reliability is usually expressed quantitatively through appropriate characteristics. In some applications, one of these characteristics is an expression of this capability through a probability, also called reliability.

Failure mechanism

Set of "cause-effect" relationships in a physical, chemical, or other process linking, the cause at the root of the failure to the failure mode.

Failure mode

One of the possible states of an entity one of whose required functions fails.

Failure cause

The circumstances during design, manufacture or use which have led to a failure.

Factor contributing to reliability – Factor affecting reliability

Technological, environment, manufacturing process or other parameter affecting the reliability of a component or system.


COTS : Commercial Off-The-Shelf
CRT    : Cathode Ray Tube
DGA    : Délégation Générale pour l'Armement
EEE     : Electrical, Electronic, Electromechanical
EIDE    : Enhanced Integrated Drive Electronic
EOS    : Electrical Overstress
ESD    : Electro Static Discharge
FIT      : Failure In Time (1 FIT equals 10-9 failures per hour)
Grms : G root mean square
LCD    : Liquid Crystal Display
MoD   : Ministry of Defence
MOS  : Mechanical Overstress
PCB   : Printed Circuit Board
PWA  : Printed Wire Assembly (PCBAssembly)
RH      : Relative Humidity
SCSI  : Small Computer System Interface
STN   : SuperTwisted-Nematic
TCy    : Thermal Cycling
TFT    : Thin-Film Transistor
TOS   : Thermal Overstress
TTF    : Time to failure