In the early 1990s, the term 'semantic' appeared in the context of text retrieval tools. However, from the very beginning of Information Retrieval as a research field (i.e. as computer-assisted identification of relevant documents), looking at the articles of Vannevar Bush (How we may think) or Luhn (The automatic creation of literature abstracts) in the 1940s and '50s, the idea of semantics was already there.
So where are we now in terms of semantics? The `latent semantic indexing` of the 1990s faded away, and the first decade of the millennium enthusiastically studied semantic web technologies. Now, in the second decade, `deep learning` is the new star. In this talk I will give a high-level overview of what has been done already, particularly in the context of the patent domain, what the main techniques are, and in which directions is the scientific community looking today. Ultimately, there will be no one answer to the question of 'What is semantic search?'. Instead, my aim is to empower the audience to ask the right questions next time somebody mentions the term.