SEO Acronyms and Abbreviations: 100+ Every Marketer Uses

SEO runs on acronyms. Walk into any marketing meeting and you’ll hear SERP, CTR, DR, LCP, GSC, and E-E-A-T used in the same sentence. If you can’t decode them in real time, you can’t participate in the conversation.

This glossary organizes 100+ SEO acronyms by category, with the full expansion and a plain-English explanation of what each one actually does for your work. Bookmark it. Reference it. Send it to anyone on your team who keeps asking what RPM stands for.

Rankings and SERP Acronyms

These define what SEO is and where it happens.

SEO — Search Engine Optimization. The practice of improving a page’s visibility in organic search results.

SEM — Search Engine Marketing. The umbrella term that includes SEO plus paid search (like Google Ads).

SERP — Search Engine Results Page. The page Google returns when you type a query. Features organic listings, ads, featured snippets, and SERP features like People Also Ask.

PAA — People Also Ask. The expandable question boxes on Google SERPs. Ranking in PAA boxes is a known tactic for capturing additional SERP real estate.

SEI — Search Engine Index. The database of pages Google has crawled and stored. If your page isn’t in the index, it can’t rank.

SGE — Search Generative Experience. Google’s AI-powered search results layer, now rebranded under AI Overviews in most markets.

AIO — AI Overviews. Google’s generative answer box that appears above traditional organic results for many queries.

GEO — Generative Engine Optimization. Optimizing content to be cited by AI search engines like ChatGPT, Perplexity, and Google AI Overviews.

AEO — Answer Engine Optimization. Similar to GEO, focused on optimizing for direct-answer engines.

LLMO — Large Language Model Optimization. Same concept, different abbreviation.

ZCS — Zero-Click Search. Queries Google answers directly on the SERP without the user clicking through to any site.

Metrics and Performance Acronyms

The numbers that determine whether your SEO work is working.

CTR — Click-Through Rate. Clicks divided by impressions. Measures how often people click your listing when they see it.

CPC — Cost Per Click. What you pay each time someone clicks a paid ad.

CPM — Cost Per Mille (thousand). Cost per 1,000 ad impressions.

CPA — Cost Per Acquisition. Total ad spend divided by conversions.

RPM — Revenue Per Mille. Revenue per 1,000 pageviews. The key ad-revenue metric for publishers.

ACoS — Advertising Cost of Sales. Ad spend divided by ad-attributed revenue. Core Amazon PPC metric.

TACoS — Total Advertising Cost of Sales. Ad spend divided by total revenue (ads plus organic).

ROAS — Return on Ad Spend. Revenue divided by ad cost. The inverse of ACoS.

ROI — Return on Investment. Net profit divided by cost, expressed as a percentage.

LTV — Lifetime Value. Total revenue expected from a customer across their relationship with you.

CAC — Customer Acquisition Cost. Total marketing spend divided by new customers acquired.

CLV — Customer Lifetime Value. Same as LTV, used interchangeably.

CVR — Conversion Rate. Conversions divided by visitors.

AOV — Average Order Value. Total revenue divided by number of orders.

MoM — Month over Month. Comparison of the current period to the previous month.

YoY — Year over Year. Comparison of the current period to the same period last year.

Core Web Vitals and Performance Acronyms

Google’s speed and stability metrics that feed ranking signals.

CWV — Core Web Vitals. Google’s three primary page experience metrics: LCP, INP, and CLS.

LCP — Largest Contentful Paint. Time until the largest visible element loads. Target: under 2.5 seconds.

INP — Interaction to Next Paint. Replaced FID in March 2024. Measures responsiveness to user interactions. Target: under 200ms.

CLS — Cumulative Layout Shift. Measures unexpected visual shifts during page load. Target: under 0.1.

FID — First Input Delay. Deprecated in 2024. Measured time from first interaction to browser response.

TTFB — Time to First Byte. Time from request to first byte received. Target: under 600ms.

FCP — First Contentful Paint. Time until the first text or image appears. Target: under 1.8 seconds.

TBT — Total Blocking Time. Sum of time the main thread is blocked between FCP and Time to Interactive.

TTI — Time to Interactive. Time until the page is fully interactive.

SI — Speed Index. How quickly content is visually displayed during page load.

Tools and Platform Acronyms

The software marketers actually use.

GSC — Google Search Console. Google’s free tool for monitoring indexing, rankings, and technical issues.

GA4 — Google Analytics 4. The current version of Google Analytics, replacing Universal Analytics (UA) in 2023.

GTM — Google Tag Manager. Container system for managing tracking tags and pixels without editing site code.

UA — Universal Analytics. Deprecated version of Google Analytics. Sunset July 2024.

BI — Business Intelligence. Category of tools for data analysis (Looker, Tableau, Power BI).

CMS — Content Management System. Software for creating and managing site content (WordPress, Drupal, Webflow).

CRM — Customer Relationship Management. Sales and customer data platforms (HubSpot, Salesforce).

SaaS — Software as a Service. Subscription-based software delivered over the internet.

MCP — Model Context Protocol. Emerging standard for AI assistants to interact with external tools and data.

Link Authority Acronyms

How third-party tools measure domain and page strength.

DA — Domain Authority. Moz’s domain-level strength score (0-100).

DR — Domain Rating. Ahrefs’ domain-level strength score (0-100).

PA — Page Authority. Moz’s page-level strength score.

UR — URL Rating. Ahrefs’ page-level strength score.

TF — Trust Flow. Majestic’s metric for link quality.

CF — Citation Flow. Majestic’s metric for link quantity.

AS — Authority Score. Semrush’s domain strength metric.

OBL — Outbound Link. A link from your page to another domain.

IBL — Inbound Link. A link pointing to your page from another site (same as backlink).

RD — Referring Domain. A unique domain that links to your site.

TLD — Top Level Domain. The .com, .org, .io suffix of a URL.

ccTLD — Country Code Top Level Domain. Country-specific TLDs like .co.uk, .de, .in.

gTLD — Generic Top Level Domain. Non-country TLDs like .com, .org, .net.

Content and NLP Acronyms

What Google uses to understand and rank your words.

E-E-A-T — Experience, Expertise, Authoritativeness, Trustworthiness. Google’s quality evaluation framework, updated from E-A-T in December 2022 to add Experience.

YMYL — Your Money or Your Life. Content categories (finance, health, legal) that Google holds to higher quality standards.

TF-IDF — Term Frequency-Inverse Document Frequency. Statistical measure of how important a word is to a document relative to a collection.

BERT — Bidirectional Encoder Representations from Transformers. Google’s 2019 NLP model for understanding search query context.

MUM — Multitask Unified Model. Google’s 2021 NLP model, 1,000x more powerful than BERT.

NLP — Natural Language Processing. The field of AI focused on understanding human language.

LLM — Large Language Model. Transformer-based AI models like GPT-4, Claude, and Gemini.

RAG — Retrieval-Augmented Generation. LLM technique that pulls external data into responses. Powers most AI search products.

GPT — Generative Pre-trained Transformer. OpenAI’s model family.

SLM — Small Language Model. Compact LLMs optimized for edge deployment.

KD — Keyword Difficulty. Estimate of how hard it is to rank for a keyword (0-100). Tool-specific scoring.

KGR — Keyword Golden Ratio. Formula for finding low-competition keywords: number of titles with exact keyword divided by monthly searches, target under 0.25.

SV — Search Volume. Estimated monthly searches for a keyword.

LSI — Latent Semantic Indexing. Outdated concept sometimes referenced in older SEO material. Google doesn’t use LSI in any practical sense.

Structured Data and Schema Acronyms

How you tell search engines what your content is.

JSON-LD — JavaScript Object Notation for Linked Data. Google’s preferred format for structured data.

RDFa — Resource Description Framework in Attributes. Older structured data format.

FAQ — Frequently Asked Questions. Schema type for Q&A content, previously eligible for rich results (changed August 2023).

HowTo — Instructional schema type for step-by-step content.

XML — Extensible Markup Language. Used for sitemaps and older structured data.

RSS — Really Simple Syndication. Feed format for publishing content updates.

AMP — Accelerated Mobile Pages. Google’s mobile-optimized framework. Declining in relevance since the Page Experience update removed AMP preference.

Technical SEO Acronyms

Infrastructure that affects how Google crawls and indexes your site.

URL — Uniform Resource Locator. A web address.

HTTP — Hypertext Transfer Protocol. Unsecured web protocol.

HTTPS — HTTP Secure. SSL-encrypted web protocol, a ranking signal since 2014.

SSL — Secure Sockets Layer. Certificate protocol for HTTPS (technically replaced by TLS, but everyone still says SSL).

TLS — Transport Layer Security. Modern successor to SSL.

CDN — Content Delivery Network. Distributed server network for fast content delivery (Cloudflare, Fastly, Akamai).

DNS — Domain Name System. Translates domain names to IP addresses.

HTML — Hypertext Markup Language. The standard markup language for web pages.

CSS — Cascading Style Sheets. Styling language for web pages.

JS — JavaScript. Programming language for interactive web functionality.

API — Application Programming Interface. How software components communicate.

REST — Representational State Transfer. Common API architecture.

CRUD — Create, Read, Update, Delete. Standard database operations.

DOM — Document Object Model. Browser’s representation of HTML structure.

SPA — Single Page Application. JavaScript-rendered apps that load one HTML page and update via JS. Harder for Google to crawl without SSR.

SSR — Server-Side Rendering. Pages rendered on the server before delivery. SEO-friendly approach for JS frameworks.

CSR — Client-Side Rendering. Pages rendered in the browser via JS. Requires careful SEO handling.

ISR — Incremental Static Regeneration. Next.js rendering strategy blending static generation with dynamic updates.

WPO — Web Performance Optimization. The broad practice of making sites faster.

Common SEO Workflow Comparison

Social and Marketing Acronyms (SEO-Adjacent)

You’ll hear these in any content marketing conversation.

PPC — Pay Per Click. Paid advertising where you’re charged per click.

UGC — User Generated Content. Reviews, comments, forum posts created by users.

CMS — Content Management System.

DMP — Data Management Platform. Centralizes audience data for marketing.

DSP — Demand-Side Platform. Programmatic ad buying platform (Amazon DSP, The Trade Desk).

ICP — Ideal Customer Profile. The type of customer most likely to succeed with your product.

MQL — Marketing Qualified Lead. Lead that meets marketing criteria for sales handoff.

SQL — Sales Qualified Lead. Lead that sales has accepted as legitimate opportunity.

KPI — Key Performance Indicator. Metric that indicates progress toward a goal.

OKR — Objectives and Key Results. Goal-setting framework.

CRO — Conversion Rate Optimization. Practice of improving the percentage of visitors who convert.

Niche but Useful Acronyms

You’ll see these less often, but they come up.

NAP — Name, Address, Phone. Core local SEO consistency elements.

GBP — Google Business Profile. Formerly Google My Business (GMB). Google’s free local listing tool.

GMB — Google My Business. Deprecated name for GBP.

VPN — Virtual Private Network. Used to check SERPs from other geographies.

UX — User Experience. How users feel using your site.

UI — User Interface. The visual and interactive elements users see.

A/B — A/B Testing. Comparing two variants to determine which performs better.

MVT — Multivariate Testing. Testing multiple variables simultaneously.

CDP — Customer Data Platform. Unified customer data infrastructure.

ETL — Extract, Transform, Load. Data pipeline process.

IPA — Integrated Performance Analytics. Emerging category for unified marketing measurement.

Why Knowing Acronyms Matters

Half of SEO is communication. You’re translating Google’s mechanics into actionable recommendations for marketers, developers, and executives who don’t speak technical SEO. Misusing an acronym in a slide deck signals that you don’t know what you’re talking about.

Misusing them internally is worse. I’ve watched teams spend a quarter chasing “DA improvement” without realizing DA is a Moz-specific metric that Google doesn’t use or acknowledge. Optimizing for a third-party score at the expense of actual business metrics is the single most common waste of SEO resources I encounter.

Use the full term when presenting to executives. Use the acronym in specialist conversations. Always know the difference between Google’s actual metrics (indexing status, Core Web Vitals, search impressions) and third-party approximations (DA, DR, KD).

Keep This Glossary Moving

SEO acronyms shift as Google updates documentation and third-party tools rebrand. BERT barely gets mentioned now that MUM and LLM-based ranking components have superseded its role. AMP appears on fewer slide decks every year. GEO didn’t exist as a mainstream term before 2024.

The acronym soup isn’t going away. But the ones that matter in 2026 aren’t always the ones that mattered in 2020. Learn the fundamentals (SERP, CTR, CWV, E-E-A-T), pay attention when Google renames something (GBP, GA4, INP), and let the rest sort itself out.

If someone drops a three-letter combo you don’t recognize, ask. The people who actually know what they’re doing won’t judge you for the question. The people who judge you for asking are usually bluffing too.