DNS, SEO, MCP: what do the words behind your website mean?

1. How a page reaches a visitor or search engine

• URL: The address of a resource, including its scheme, hostname and path.
• HTTP status: The server’s response category and result.
• Redirect: An instruction to request another address.
• Crawl: A crawler discovers and requests URLs.
• Render: The browser or search engine builds a page, possibly running JavaScript.
• Index: A search engine processes and stores eligible content for retrieval.
• Canonical: A signal identifying the preferred URL among duplicate or closely related pages.
• Noindex: A directive asking search engines not to index a resource.

MDN’s status reference · robots and indexing guide

2. Search structure and page meaning

• SEO: Search engine optimization helps engines understand content and people find relevant pages.
• Robots.txt: A host-level file that gives participating crawlers access instructions.
• Sitemap: A file listing URLs you want search engines to discover.
• Hreflang: Annotations linking equivalent language or regional versions.
• Title: The page’s title element describes its subject and helps distinguish it from other pages.
• Meta description: A concise page summary that may inform the search snippet.
• Structured data: Machine-readable markup describing supported entities and relationships.

Google SEO guide · localized-version guidance · technical SEO guide

3. Transport, browser policy and domain email

• TLS: Transport Layer Security encrypts traffic and authenticates the server through certificates.
• CSP: Content Security Policy sets browser rules for resources and other behaviors, including embedding.
• HSTS: HTTP Strict Transport Security tells browsers to use HTTPS for a host.
• DNS: The Domain Name System publishes records used for addresses, mail routing and other policies.
• SPF: Sender Policy Framework specifies authorized sending sources for an envelope-sender domain.
• DKIM: DomainKeys Identified Mail uses a domain signature to verify signed message content.
• DMARC: Domain-based Message Authentication, Reporting, and Conformance compares the visible From domain with a domain authenticated by SPF or DKIM and lets domain owners publish an email-handling policy.
• CAA: Certification Authority Authorization records specify which certificate authorities may issue certificates for a domain.
• CVE: A Common Vulnerabilities and Exposures identifier gives a specific cybersecurity vulnerability a shared reference.

OWASP’s header guidance · DMARC specification · TLS and headers · DNS and email

4. From observations to useful decisions

• Finding: An observation that deserves interpretation or action.
• Evidence: The recorded facts supporting an observation: URL, response, value or reproducible behavior.
• Severity: The estimated seriousness of a finding in its technical context.
• Confidence: How strongly the available evidence supports the conclusion.
• Port: A numbered network endpoint used by a service.

website audit workflow

5. Loading, interaction and measurement conditions

• LCP: Largest Contentful Paint measures when the largest eligible visible content appears.
• INP: Interaction to Next Paint measures responsiveness across page interactions.
• CLS: Cumulative Layout Shift measures unexpected visual movement using qualifying shift clusters.
• TTFB: Time to First Byte measures the wait until the response begins, including network and server time.
• Lab data: Measurements from a controlled test with specified device and network conditions.
• Field data: Measurements collected from actual visits under varied conditions.
• CrUX: The Chrome User Experience Report aggregates eligible real-user Chrome experience data.

Web Vitals guidance · performance guide

6. Making controls and content usable

• Label: The name that explains a form control’s purpose, ideally visible and programmatically associated.
• Alt text: A text alternative conveying an image’s purpose in context.
• Keyboard access: The ability to operate a page without a pointer.
• Contrast: The visual distinction between text and background, evaluated in WCAG using a ratio of their relative luminance.

W3C contrast explanation · accessibility guide

7. Analytics and connected services

• Integration: A connection between systems or services, often using a script or API.
• Event: A message describing an action, such as an account signup or a completed purchase.
• Consent: A user’s choice about a specified use of their data where consent is required.

integrations guide

8. AI content readiness and observable visibility

• AI readiness: Content and technical qualities that help machines access, interpret and attribute information.
• Citation: A source reference attached to an AI answer or another published claim.
• Entity: An identifiable person, organization, product or other concept.

Google’s AI feature guidance · AI visibility guide

9. Connecting an assistant and proving site access

• MCP: Model Context Protocol standardizes how AI applications connect to tools and data.
• OAuth: An authorization framework through which an application receives permission to access selected resources using tokens.
• Access token: A credential representing granted access, usually with a scope and lifetime.
• Domain verification: Evidence that an account controls or is authorized to verify a target domain through a supported method.

MCP architecture · OAuth framework

Put the vocabulary into practice with Sitelemetry

Sitelemetry brings these topics into a common website review. Use the definitions to understand the observations, discuss useful improvements with your team and follow the related guides as you develop the site.