---
title: Glossary
description: Definitions for terms used across Cloudflare DNS documentation.
image: https://developers.cloudflare.com/core-services-preview.png
---

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# Glossary

Review the definitions for terms used across Cloudflare's DNS documentation.

| Term                     | Definition                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| active zone              | A DNS zone that is active on Cloudflare requires changing its nameservers to Cloudflare's for management.                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| apex domain              | Apex domain is used to refer to a domain that does not contain a subdomain part, such as example.com (without www.). It is also known as "root domain" or "naked domain".                                                                                                                                                                                                                                                                                                                                                                                                            |
| CNAME setup              | Also known as partial setup, a CNAME setup allows you to use Cloudflare's reverse proxy without using Cloudflare for your authoritative nameservers.                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| DNS over HTTPS           | DNS over HTTPS (DoH) is a standard for encrypting DNS traffic via the HTTPS protocol, preventing tracking and spoofing of DNS queries.                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| DNS over TLS             | DNS over TLS (DoT) is a standard for encrypting DNS traffic using its own port (853) and TLS encryption.                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| DNS record               | DNS records are instructions that live in authoritative DNS servers and provide information about a domain, including what IP address is associated with that domain and how to handle requests for that domain.                                                                                                                                                                                                                                                                                                                                                                     |
| DNS server               | DNS servers translate human-readable domain names into IP addresses, eliminating the need to remember complex IP addresses.                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| DNS zone                 | A portion of the DNS namespace that is managed by a specific organization or administrator.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| Domain Name System (DNS) | The Domain Name System (DNS) is the phonebook of the Internet. DNS translates domain names to IP addresses.                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| EDNS Client Subnet (ECS) | ECS is a DNS extension that enables recursive DNS resolvers to include client IP address information in their DNS queries. Not all resolvers use ECS but, if they do, usually a part of the IP address is omitted. Sending ECS headers is generally intended to reduce latency and speed up content delivery in connection to [CDNs](https://developers.cloudflare.com/glossary/?term=cdn) and [load balancers](https://www.cloudflare.com/learning/performance/what-is-load-balancing/). The ECS mechanism is specified in [RFC 7871](https://www.rfc-editor.org/rfc/rfc7871.html). |
| hostname                 | The name given to a server or node on a network, often the public DNS name of a server.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| nameserver               | A nameserver is a dedicated server that translates human readable hostnames (www.example.com) into IP addresses. Nameservers like root servers, TLD servers, and [authoritative nameservers](https://developers.cloudflare.com/dns/nameservers/) are fundamental components of the Domain Name System (DNS).                                                                                                                                                                                                                                                                         |
| proxy status             | The proxy status of a DNS record defines whether requests for your domain will route through Cloudflare (proxied) or not (DNS-only). When a [DNS record is proxied](https://developers.cloudflare.com/dns/proxy-status/), requests are processed according to your configurations, and Cloudflare can optimize, cache, and protect your domain. Refer to [How Cloudflare works](https://developers.cloudflare.com/fundamentals/concepts/how-cloudflare-works/) for details.                                                                                                          |
| zone apex                | Zone apex refers to the domain or subdomain on which the control of DNS records starts.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |

```json
{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/dns/","name":"DNS"}},{"@type":"ListItem","position":3,"item":{"@id":"/dns/glossary/","name":"Glossary"}}]}
```