Keyword search matches the words of the search term. Semantic search compares meanings: Typesense turns each product and each search term into an embedding vector, and ranks products by the distance between the vectors. A search for "footwear for jogging" then finds a product named "Running Shoe", which has none of those words.
Semantic search needs the Typesense engine. The database engine rejects the SEMANTIC and HYBRID modes.
Sign in with your Vendure Console account to read this documentation.