AI Search Glossary: Terms Every Marketer Should Know

Half of all B2B buyers now start their research with AI chatbots instead of Google. If you're still speaking only the language of traditional SEO, you're missing the conversation.

AI search has created an entirely new vocabulary. Generative Engine Optimization. AI Share of Voice. Citation Rate. Brand Recommendation Rate. These aren't buzzwords—they're the metrics that determine whether your brand gets mentioned when someone asks ChatGPT or Perplexity for recommendations in your category.

I built this glossary because the AI search space moves fast and the terminology is confusing. GEO, AEO, LLMO—they all sound the same until you understand what each one actually means. Some terms are technical (like Retrieval-Augmented Generation). Others are strategic (like AI Brand Monitoring). All of them matter if you want to show up in AI-generated answers.

This isn't an exhaustive encyclopedia. It's a working reference. The terms here are the ones that come up in actual conversations with marketers trying to figure out how to get their brands cited by AI. Use it to get up to speed, then bookmark it for when you inevitably forget what PerplexityBot does or why JSON-LD matters.

Core AI Search Concepts

Let's start with the foundational terms. These are the concepts you need to understand before anything else makes sense.

Generative Engine Optimization (GEO) is the practice of optimizing content and brand presence to increase visibility in AI-generated answers. Unlike SEO, which focuses on ranking in search results, GEO focuses on getting cited as a source when AI platforms like ChatGPT, Perplexity, or Google AI Overviews generate answers. It combines content structure, digital PR, technical implementation, and entity optimization.

Answer Engine Optimization (AEO) is often used interchangeably with GEO, though some practitioners draw distinctions. AEO technically refers to optimizing for any system that generates direct answers—including traditional featured snippets and knowledge panels, not just AI-powered responses. For most practical purposes, GEO and AEO address the same challenge.

AI Visibility measures how often and how prominently your brand appears in AI-generated responses. Think of it as the AI equivalent of search engine rankings. High AI visibility means your brand gets mentioned, cited, and recommended frequently across platforms like ChatGPT, Perplexity, Gemini, and Google AI Overviews.

AI Share of Voice is the percentage of AI mentions your brand receives compared to competitors within a specific category or set of queries. If ChatGPT recommends project management tools and mentions your brand in 3 out of 10 responses, you have a 30% share of voice for that query set.

Zero-Click Search occurs when users get their answer directly on the search results page without clicking through to a website. Google AI Overviews create a 27% zero-click rate on desktop and 75% on mobile. This fundamentally changes content strategy—the goal shifts from driving clicks to earning citations.

AI Platforms & Technology

Understanding the platforms themselves helps you optimize for each one differently.

ChatGPT Search is OpenAI's search feature that allows ChatGPT to browse the web in real-time and cite sources. With 4.5 billion monthly visits, ChatGPT is now one of the largest information discovery platforms in the world. Wikipedia accounts for 47.9% of its citations.

Perplexity AI is an AI-powered search engine that provides cited answers to queries. It processes over 500 million monthly searches. Perplexity indexes content much faster than ChatGPT—changes can appear in results within days rather than weeks.

Google AI Overviews are AI-generated summaries that appear at the top of Google search results. They show up in over 30% of searches. Google and Microsoft confirmed in March 2025 that structured data helps AI features surface content, and pages with FAQ sections nearly double their chances of being cited by ChatGPT (SE Ranking 2025).

Google AI Mode is Google's conversational search experience, currently in limited rollout. It provides a more interactive, ChatGPT-like interface within Google Search.

Gemini is Google's AI assistant and large language model family. It powers Google AI Overviews and integrates across Google Workspace products.

Large Language Model (LLM) is the underlying technology behind AI assistants like ChatGPT, Claude, and Gemini. LLMs are trained on massive text datasets and can generate human-like responses. Understanding how LLMs work helps you optimize content for AI citation.

Retrieval-Augmented Generation (RAG) is the technique AI systems use to fetch relevant information from external sources before generating an answer. When ChatGPT searches the web or Perplexity pulls from its index, that's RAG in action. Optimizing for RAG means making your content easy for AI systems to find and extract.

Technical Implementation

These are the technical elements that make content more discoverable and citable by AI.

Schema Markup is structured data vocabulary that helps search engines and AI systems understand your content. Google and Microsoft confirmed in March 2025 that they use schema markup for their generative AI features, making structured data important for AI visibility. Pages with sections of 120-180 words between headings receive 70% more ChatGPT citations, according to SE Ranking's 2025 study of 129,000 domains.

JSON-LD is the recommended format for implementing schema markup. It's a script tag you add to your HTML that contains structured data in JSON format. AI systems can parse JSON-LD easily, making it the preferred method for entity and content markup.

FAQ Schema structures frequently asked questions in a machine-readable format. It's particularly effective for AI visibility because it creates clear question-answer pairs that AI can extract and cite directly.

llms.txt is a proposed standard file (similar to robots.txt) that helps LLMs understand a website's content structure. It's still early-stage but gaining adoption among sites that want to provide AI-friendly content maps.

AI Crawlers are bots that index web content for AI training and real-time retrieval. GPTBot (OpenAI), ClaudeBot (Anthropic), and PerplexityBot are the main ones. Blocking these in robots.txt prevents your content from being used in AI responses.

Entity Optimization involves structuring your brand information so AI systems recognize and understand your company as a distinct entity. This includes maintaining consistent profiles on Wikidata, Crunchbase, and knowledge bases, plus implementing Organization schema markup.

Measurement & Monitoring

You can't improve what you don't measure. These terms define how to track AI search performance.

AI Brand Monitoring is the practice of tracking what AI platforms say about your brand. It includes monitoring mentions, citations, sentiment, share of voice, and recommendation rates across ChatGPT, Perplexity, Google AI Overviews, and other AI search platforms.

Citation Rate measures how often AI systems cite your content as a source when generating answers. Higher citation rates indicate strong AI visibility and content authority.

Brand Recommendation Rate tracks how frequently AI platforms recommend your brand when users ask for options in your category. This is the AI equivalent of ranking #1 for commercial keywords.

AI Brand Sentiment analyzes whether AI systems describe your brand positively, negatively, or neutrally. Unlike social media sentiment, AI sentiment compounds—negative framing in training data can persist for months.

AI Hallucination occurs when an AI system generates false or fabricated information about your brand. Hallucinations happen when the model lacks accurate data or misinterprets training information. Correcting them requires publishing authoritative, structured content and building strong entity signals.

Content Strategy Terms

These concepts guide how you create and structure content for AI visibility.

E-E-A-T stands for Experience, Expertise, Authoritativeness, Trustworthiness. Google's quality framework for evaluating content. Content with strong Authors with visible credentials receive 40% more citations from AI models (Qwairy 2026) in AI responses. This means named authors, first-person experience, citations to authoritative sources, and clear expertise signals.

Digital PR is the practice of earning brand mentions and coverage on authoritative websites. In AI search, digital PR has become even more valuable—brand mentions are the #1 correlation with AI visibility. Authoritative list mentions drive 41% of AI brand recommendations.

AI Citation refers to when an AI system references your content or brand as a source in a generated response. Citations can be explicit (with a link) or implicit (mentioning your brand without a link).

AI Brand Mention occurs when AI platforms name your brand in generated responses, whether as a recommendation, example, or reference. Even without a citation link, mentions build brand awareness and credibility.

Why This Vocabulary Matters

Here's the thing about new terminology—it signals that something fundamental has shifted.

When we started talking about "SEO" in the late 1990s, it was because a new distribution channel (search engines) required a new optimization discipline. The same thing is happening now with AI search. GEO isn't just SEO with a new acronym. It's a different game with different rules, different signals, and different metrics.

You don't need to memorize every term in this glossary. But you do need to understand the concepts well enough to make strategic decisions. Should you block GPTBot in robots.txt? That depends on whether you want your content used in ChatGPT responses. Should you invest in schema markup? Absolutely—it's improved AI citation potential through structured data is one of the clearest ROI opportunities in AI visibility.

The marketers who win in AI search aren't the ones who learn the jargon fastest. They're the ones who understand what the jargon represents and act on it before their competitors do. AI visibility tends to build on itself as brands become established references—first movers get exponentially harder to displace.

Bookmark this page. The terminology will evolve as the space matures, and we'll keep this glossary updated as new concepts emerge and old ones get refined.