What is Reliability?
Reliability is the ability of a system or component to perform its intended function under specified conditions for an extended period without failure. A reliable product has a high probability of performing as expected over time. The reliability of a product can be measured by how long it will last before failing and how often it fails.

In other words, a reliable product does not fail. It performs consistently and predictably.
The following are some examples of products that have been designed with reliability in mind:
- A car engine that starts every time you turn the key.
- An airplane that flies safely through turbulence.
- A medical device that works properly when used on patients.
- A refrigerator that keeps food fresh.
- A telephone switchboard that connects calls correctly.
- A nuclear power plant that operates safely.
Conclusion
Reliability is one of the eight dimensions of product quality defined by Garvin.