Final semantic search
November 2023
5 Mins
Scott Ansell Developer

Unlocking the Power of Semantic Search

In today's digital age information is vast and constantly growing, making it challenging to find the right content quickly and efficiently. Traditional keyword-based search engines often fall short when it comes to understanding the context and semantics of user queries. This is where semantic search and embeddings come into play - by integrating these into search engines and conversational agents we can redefine the way we discover and retrieve information.

Vectors: The Building Blocks of Semantic Search

At the core of semantic search and embedding lies the concept of vectors. In the context of natural language processing (NLP) and machine learning, vectors are mathematical representations of words, phrases, or documents. These vectors are created through a process known as embedding which converts textual information into numerical form. Think of it like a vast library, a Vector is the index of where text belongs on a shelf or in a book. The indexes are arrays of numerical values where each value corresponds to a specific feature or aspect of the embedded data. Vectors are derived from statistical patterns and relationships within trained data.

Embedding services (like OpenAI) can create vectors for individual words by analysis of extensive text data, capturing relationships and contextual meanings. For example, in a well-trained model, 'cat' and 'dog' vectors would be close, reflecting their semantic similarity.

Beyond individual words, large documents and chunks of text can be embedded. By considering the context and relationships between words within a document, these techniques create embeddings that encapsulate the overall meaning of the text.

Vectors not only encode the words' semantics but also capture syntactic and contextual information. This rich representation enables the system to grasp the meaning of words and documents in a way that traditional keyword-based search engines cannot.

A small snippet of a vector

Comparing Vectors: Unlocking Semantic Search

Once vectors are generated for words and documents, they can be compared in various ways to perform semantic search and retrieval:

Cosine Similarity: Cosine similarity is a common method used to compare vectors. It measures the cosine of the angle between two vectors, where a smaller angle implies higher similarity. In semantic search, documents or words with vectors that have a high cosine similarity are considered semantically related.

Euclidean Distance: Euclidean distance calculates the straight-line distance between two vectors in a multi-dimensional space. Smaller distances imply higher similarity. This metric is useful when you want to measure the dissimilarity between vectors.

Clustering and Classification: Vectors can also be used for clustering similar documents or for classifying text into predefined categories. This enables efficient content organisation and recommendation systems.

Cosine comparisons of two vectors


Semantic search and embedding have opened new horizons in information retrieval and understanding. By converting words and documents into numerical vectors and comparing them, these technologies enable more accurate and context-aware search experiences. As the field of NLP continues to advance, we can expect even more powerful capabilities that make finding and understanding information in the digital world easier than ever before!