# Predicate Terminology

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## Definition: Predicate

Any function that accepts exactly one input and produces a
[Predicate Result](#definition-predicate-result) (aka a Boolean output).

Predicates are ways to express logical conditions.

## Definition: Predicate Result

The result of evaluating a [Predicate](#definition-predicate). Predicates may:

- [Match](#definition-match)
- [Miss](#definition-miss)

## Definition: Match

The term **match** is a specific [Result](#definition-predicate-result).
Semantically, it means that the predicate ran successfully against the given
input. The conditions within were met.

If the predicate were expressed as a Boolean, this would correspond to `true`.

## Definition: Miss

The term **miss** is a specific [Result](#definition-predicate-result).
Semantically, it means that the predicate did not run successfully against the
given input. The conditions within were not met.

If the predicate were expressed as a Boolean, this would correspond to `false`.