---
last_review: "2026-05-06"
last_reviewer: "-"
documented_code: []
---
```{tags} user
```

# Glossary

## General terms ##

:::{glossary}

API
    Application Programming Interface. See [Wikipedia:API](https://en.wikipedia.org/wiki/API)

Data Model
    A high-level abstract representation of how data is organized in a system (for example
    entity‑relationship, document, key‑value). Not to be confused with {term}`Schema`. See
    the [data model and schema tutorial](/tutorial/introduction/datamodel_and_schema).

Schema
    A concrete specification of the structure for a particular dataset or database instance based on
    a {term}`data model <Data Model>` (e.g., tables/columns and types in SQL, JSON Schema for
    documents). It lists fields, types, constraints, and optionally default values.

Vocabulary
    A set of terms used to describe a domain of interest (e.g., "Person", "birthDate", "worksAt").
    In the context of a {term}`Schema`, the terms are the names of the Schema's components (fields,
    types, classes).

:::

## LinkAhead's data model ##

:::{glossary}

Record
    Represents individual thing - a single person named "Alice", a particular sample with bar code
    "xyz". See the [data model and schema tutorial](/tutorial/introduction/datamodel_and_schema).

RecordType
    Represents universals, classes, concepts, categories. Every Record has a RecordType.
    See the [data model and schema tutorial](/tutorial/introduction/datamodel_and_schema).

Parent
    All {term}`Entities <Entity>` can have parents. {term}`Records <Record>` must have parents.
    A parent is the more abstract or more general description of the respective {term}`Entity`.
    See the [data model and schema tutorial](/tutorial/introduction/datamodel_and_schema).

Property
    Represents the properties of both individuals and universals, e.g., the hair color is a 
    property of a person.
    See the [data model and schema tutorial](/tutorial/introduction/datamodel_and_schema).

Entity
    {term}`Records <Record>`, {term}`RecordTypes <RecordType>`, {term}`Properties <Property>`
    and Files in LinkAhead can all referred to as Entities.
    See the [data model and schema tutorial](/tutorial/introduction/datamodel_and_schema).

File
    Represents a binary file, which can be downloaded.
:::

## Other terms ##

:::{glossary}
CFood
    The specification in YAML format that defines which data is matched by the crawler and
    how it is mapped to {term}`Records <Record>` in LinkAhead.
    See documentation in [](/explanation/crawler/index.md#cfoods).

Crawler
    The main data integration tool used by
    LinkAhead. See documentation in [](/explanation/crawler/index.md).

LQL
    [LinkAhead Query Language](/explanation/general/linkahead_query_language.md), the textual
    representation to ask LinkAhead for data.

POV filter
    Short for property-operator-value filter. A filter in {term}`LQL` that restricts results
    based on the value of a property, for example `property1=value1`.
    See the [LQL reference](/reference/general/lql_reference.md#property-filters).

StructureElement
    Each element in a hierarchical structure that can be integrated by the {term}`Crawler <crawler>`
    is represented by a StructureElement.
    See documentation in [](/explanation/crawler/index.md#structure-elements).

:::