I'm personally not very concerned with tags - I'm not sure the body of 800 or so questions we have is in need of more structured and logic tag organization.
However there are many kinds of searches related to patents. If I say I'm going to "search patents", I'm clearly looking through patent documents. But the largest use of "patent search" is meant to indicate a patent novelty search or prior art search. A patent novelty search is not strictly a search of patents, it is a search for anything that would show an actual or proposed patent claim to not be new. So in most cases "a patent search" is a search of both patent and non-patent literature.
I think they are used for similar questions and there is no visible differentiation so they should be duplicates. I don't have enough reputation on either tag to suggest a synonym, but I'd prefer patent-search over search.