DNS propagation
A colloquial name for DNS changes becoming visible as cached copies expire. It is not one global switch; TTL and the user's resolver matter.
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Glossary
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DNS PTR record
A record pointing to a name, commonly used in reverse DNS. For public IPs, the address provider usually configures it rather than any domain administrator.
Definition and sourcesDNS server
A service handling DNS-data queries. Recursive resolvers and authoritative servers have different roles; not every server should allow public recursion.
Definition and sourcesDNS SRV record
A record locating a service by host, port, priority and weight. Clients must support SRV; it does not automatically relocate every web service.
Definition and sourcesDNS TXT record
A text-bearing DNS record used for domain verification and mail policies. The applicable specification or service defines its value's meaning.
Definition and sourcesDNS-based Authentication of Named Entities
A mechanism publishing TLS authentication information in DNSSEC-protected TLSA records. DANE requires client support and a valid DNSSEC chain.
Definition and sourcesDNSSEC
DNS extensions authenticating response origin and integrity through signatures. DNSSEC does not encrypt queries or certify a website's safety.
Definition and sourcesDocker
A platform for building and running application containers. Containers usually share the host kernel; they are not automatically full virtual machines or absolute isolation boundaries.
Definition and sourcesDofollow link
A colloquial name for an ordinary link without nofollow qualification. Dofollow is not a standard HTML attribute; its absence does not guarantee ranking benefits.
Definition and sourcesDolphin PHP
A name associated with BoonEx's Dolphin social-network platform. Older deployments require separate verification of support and update availability.
Definition and sourcesDomain Authority
Moz's proprietary metric modelling a domain's comparative ranking potential. It is not a Google score; similarly named third-party metrics use different calculations.
Definition and sourcesDomain name
A name within the DNS hierarchy, such as syntimo.com. It can support websites, email and other services. A domain is neither the website nor hosting; registration does not automatically create content.
Definition and sourcesDomain Rating
Ahrefs' metric describing the relative strength of a domain's backlink profile. It does not directly measure traffic, overall quality or a Google-assigned score.
Definition and sourcesDomain registrant change
A change of the domain registrant holding registration rights. It differs from transferring management to another registrar.
Definition and sourcesDomain transfer authorisation code
An authorisation code used to transfer a domain between registrars. Keep it confidential; procedures and code validity depend on the domain registry.
Definition and sourcesDomain-driven design
Software design centred on the domain model and a shared team language. Bounded contexts separate meanings between areas of a system.
Definition and sourcesDomainKeys Identified Mail
A mechanism signing selected email elements with a domain key. Receivers verify signatures through DNS; DKIM does not encrypt message content.
Definition and sourcesDouble opt-in
A subscription process requiring an additional confirmation, usually through an emailed link. It helps verify address control but does not replace valid consent wording.
Definition and sourcesDropdown menu
A menu opened by activating a control. It needs a clear name, keyboard support and correct focus management; hover alone is insufficient.
Definition and sourcesDropshipping
A retail model where a supplier ships directly to the store's customer. It does not remove the seller's order, information and customer-service responsibilities.
Definition and sourcesDrupal
An open-source CMS with modules, content modelling and access control. Environment requirements and support schedules matter when choosing a version.
Definition and sourcesDTP (Desktop Publishing)
Preparing publication layouts on a computer, including text composition, graphics and production files. Examples include books, catalogues and PDFs. Printed material must also meet the printer's technical specifications.
Definition and sourcesDuplicate content
Identical or very similar content under different URLs. It can split signals and complicate canonical selection; it does not imply an automatic penalty.
Definition and sourcesDwell time
A colloquial term for time between visiting a search result and returning to results. It differs from session duration and is not a confirmed simple Google factor.
Definition and sources