There are various types of faults:

• In document ISO/CD 10303-226 , a fault is defined as an abnormal condition or defect at the component, equipment, or sub-system level which may lead to a failure.

According to Federal Standard 1037C, the term fault has the following meanings:

1. An accidental condition that causes a functional unit to fail to perform its required function.
2. A defect that causes a reproducible or catastrophic malfunction. A malfunction is considered reproducible if it occurs consistently under the same circumstances.
3. In power systems, an unintentional short-circuit, or partial short-circuit, between energized conductors or between an energized conductor and ground. A distinction can be made between symmetric and asymmetric faults.

See also: Defect, Computer bug

• A geologic fault is a crack or joint between two blocks of earth (usually tectonic plates) that are moving or have moved relative to each other. Earthquakes often occur along faults.

• A fault, in animal breeding, is a conformation point whose state or quality falls outside of the acceptable range for the attribute being judged.