SEM (Search Engine Marketing)

There’s also the concept of “semantic search”

which means to search/research for keywords, but get results matching synonyms and related words/phrases of those keywords. When browsing a blog/news or ecommerce site, you see “suggested” or “related” content in the sidebar. That can be “semantic search”. Or when searching Google for a word, it will give you results of similar keywords. That’s exactly it.
OpenAI offers a text vector/similarity analysis product called embeddings.
More about OpenAI search.
A more commercially established product:
Algolia also specializes in this and has the most mature product offering.