# Glossary

This page lists out terms reused across pages in this section, and links to where they are introduced. A more complete list can be found in the [TypeQL reference](../../../typeql-reference/keywords/index.md).

*   [Annotation](../constraining-data/index.md#definition-annotation): Language fragments mainly used to add additional constraint to types.
    
*   [Answer](../query-variables-patterns/index.md#definition-answer): A mapping of variables to the concepts the pattern "matched" in the database.
    
*   [Bound variable](../query-variables-patterns/index.md#definition-bound): A variable which has been mapped to a concept.
    
*   [Concept](../query-variables-patterns/index.md#definition-concept): An umbrella term for a type, an instance of a type or value.
    
*   [Constraint](../query-variables-patterns/index.md#definition-constraint): An atomic sentence of the TypeQL language. Broadly, constraint is used in two senses:
    
    *   The schema is a collection of "constraints" on and between types - what values can a certain attribute type hold? What attributes can an entity/relation own, and what roles can they play?
        
    *   The pattern in a match clause consists of "constraints" between variables that the concepts matched must satisfy.
        
    
*   [Interface polymorphism](../entities-relations-attributes/index.md#definition-interface-polymorphism): The polymorphism enabled by allowing different types to implement the same interface (play the same roles, or own the same attribute)
    
*   [Pattern](../query-variables-patterns/index.md#definition-pattern): A set of constraints describing the data to match or insert.
    
*   [Preamble](../queries-as-functions/index.md#definition-preamble): A collection of functions preceding a query, valid for that query only.
    
*   [Specialization](../entities-relations-attributes/index.md#definition-specialisation): Restricting an inherited interface, so it may be implemented by a more specific set of types.
    
*   [Variable](../query-variables-patterns/index.md#definition-constraint): A placeholder for a concept in a pattern.
    

[Advanced: Invalid Patterns](../invalid-patterns/index.md) [Drivers](../../drivers/index.md)

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