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.
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.
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.
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.
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