GEO / AI search

Embedding

Also known as: Vector embedding, Text embedding, Semantic vector

An embedding is a numerical vector representation of a piece of text (a word, sentence, paragraph or entire article) that encodes its semantic meaning in a high-dimensional space (typically 768–3,072 dimensions). Two texts with similar meaning have embeddings that sit close together in the vector space — even if they use none of the same words. Embeddings are the basis for semantic search, retrieval augmented generation, topic cluster detection and many other NLP applications.

How embeddings are created

Dedicated embedding models (OpenAI text-embedding-3, Cohere Embed, Voyage AI, open-source models such as BGE-M3) convert an input text into a float vector. The model has been trained on vast text corpora to learn semantic similarity — sentences such as ”How fast does my website load?” and ”measuring page speed” end up with vectors that sit close together, even though they share no common word. Similarity is typically measured as cosine similarity or dot product.

Embeddings in AI search

The retrieval phase of modern AI search engines almost always runs on embeddings: (1) the user query is converted into a vector; (2) a vector database looks for the K nearest vectors (that is, the semantically most similar content); (3) this content is passed to the LLM as context. The effect for GEO: content written broadly and coherently around a topic has ”better” embeddings — it sits closer in the vector space to a variety of related queries. Narrow keyword-stuffed texts occupy a narrow position in the embedding space and are retrieved less often for thematically broad queries.

What this means for content strategy

Example from practice

Example: two articles on the topic of ”visibility in AI search”. Article A uses the main keyword 50 times in 600 words, without any further terms. Article B covers thematically related aspects (citation rate, entity linking, RAG, Schema.org markup, brand authority) across 1,800 words. Across Perplexity queries using 12 different long tail formulations, article B is retrieved and cited in 9 cases, article A in 2 cases. The reason: in the embedding space article B has far broader topic coverage — it is recognised as ”semantically close” to more related queries.

Frequently asked questions

What is an embedding?
An embedding is a vector representation of text (or an image or audio) in a high-dimensional numerical space. Similar meanings sit close together in the vector space. It is the foundation of modern semantic search and RAG systems.
What are embeddings used for?
For similarity search: given a question, find the semantically most similar documents. The classic approach is full-text search based on word matches. The modern approach is embedding search, which recognises conceptual similarity (”car” ≈ ”vehicle”). RAG systems depend on embeddings.
How are embeddings generated?
Through embedding models: OpenAI text-embedding-3, Google Vertex AI Embeddings, Cohere Embed, open-source models such as E5 or BGE. Input: a text chunk. Output: a vector with, in most cases, 384–3,072 dimensions. They are stored in vector databases (Pinecone, Weaviate, PostgreSQL pgvector).
Can SEOs use embeddings directly?
Increasingly, yes. Semantic content analysis, keyword cluster building and content similarity checks all use embeddings. Rankmio uses PostgreSQL pgvector in the backend for the Content Studio RAG library and semantic competitor analysis.

Used in Rankmio for

Topic breadth check in the Content Studio

Go to the feature →

Last updated: 2026-06-17  ·  Browse all glossary entries

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