---
language: en
title: "Cited domain"
description: "A cited domain groups URLs referenced in AI responses. Learn how to define the unit of analysis without confusing pages, subdomains, and visits."
canonical: "https://tropk.ai/en/resources/glossary/cited-domain"
last_modified: "2026-10-12T16:12:34.017Z"
---

# Cited domain

Reviewed on 2026-10-06.

## What it means

A cited domain is the domain of a URL presented as a reference in an [AI response](/en/resources/glossary/ai-response). Grouping citations by domain lets you see which sites appear in the sample while retaining the URLs for further investigation. The report should state whether it uses the full host name, including subdomains, or the registrable domain determined with the help of the Public Suffix List.

## Why it matters for marketing

This unit helps marketing teams identify recurring publishers and distribute the analysis of external content. However, five pages from the same site do not represent five domains. Without a grouping rule, a change in the report may look like source diversification when it has simply started counting the publisher’s news section and help center separately.

## Example in practice

Suppose a software company finds six URLs cited in a sample: four from articles and two from help pages, all under the same registrable domain. The previous report separated the two subdomains. The analyst regroups them using the stated rule and retains all six URLs, avoiding presenting two independent sites to the public relations team.

## How to apply or verify

Extract the host from each URL actually cited and apply the same normalization rule throughout the period. If grouping by registrable domain, use a library that is up to date with the Public Suffix List; do not simply cut off the last two parts of the name. Manually check relevant subdomains and retain the response, original URL, and aggregated domain for auditing.

## Important distinctions

A domain, URL, and organization responsible for a site are not equivalent units. A domain may contain multiple pages and content by different authors; grouping them does not prove consistent quality. A [citation](/en/resources/glossary/ai-citation) also does not indicate human access, traffic, or sales. To measure frequency, state whether you count occurrences, distinct responses, or unique domains, and keep the denominator visible in the report.

## Sources and references

- [Public Suffix List](<https://publicsuffix.org/>) — Public Suffix List
- [Web search](<https://developers.openai.com/api/docs/guides/tools-web-search>) — OpenAI

## Continue a leitura

- [Aggregation by page and domain](</en/resources/glossary/aggregation-by-page-and-domain>)
- [Inline citation](</en/resources/glossary/inline-citation>)
- [Citation share](</en/resources/glossary/citation-share>)

## About the author

[Luiz Gardelin](</en/team/luiz-gardelin>)

Luiz Gardelin is the founder of Tropk.ai and works in GEO/AEO, product vision, strategy, and growth, helping brands understand and improve their presence in AI responses.

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