LSI or latent semantic index is a set of words that help the search engine understand what exactly the user wants to find or, in other words, these are words that set the subject matter of the query.
To better understand, let’s take the query “key”, what should the search engine show: a wrench, a door key, a car key, or a word in the text? The search engine does not know this either, so in search suggestions, Google instantly adds words to the query “key” and the user often clicks them and gets the result for the longer refined query “door key”.
Knowing the list of these words, you can create an article by responding in advance to queries that the user “specifies” and be one step ahead of competitors and higher in the search results.