the quality of being dependable or reliable
"We chose that car brand specifically for its reputation regarding reliability, knowing we wouldn't face unexpected breakdowns on our long road trips."
The quality of being reliable, dependable, or trustworthy.
"The reliability of that engine is legendary, as it has never failed me during a cross-country trip."
In plain English: Reliability is how much you can trust someone to do what they say they will do.
"The reliability of this brand has made me buy several more products over the years."
Usage: Reliability refers to the consistent ability to perform as expected without failure. Use this term when describing systems, people, or data that can be trusted over time rather than just once.
The word reliability comes from combining the adjective reliable with the suffix -ity to form a noun. It entered English as a straightforward derivation that describes the quality of being able to be trusted or depended upon.