Latent semantic indexing
Latent semantic indexing (LSI) is a term that refers to the ability of search engines to co-determine search results on keywords that have a relevant connection to the main keyword. Semantic keywords are keywords that are an extension of and thus related to the main keyword on which content is designed.
Latent semantic indexing, then, is a term which describes Google's ability to "read comprehensively," that is, the concept Google uses to discover how the search term and the content in question mean the same thing.
If these LSI keywords are not incorporated into the content, it takes the search engines much more effort to search for these synonyms and especially the relationship of the keywords used to the content on the website. Latent semantic indexing stands in a direct relationship to the findability of a Web site.
A web page where there is no combination between the main keyword and LSI keywords will be a lot less findable because this page is often not displayed in a frequently visited spot in the search results. So using these keywords is a form of search engine optimization. An additional advantage (and not the least important point) is that by using LSI keywords, a text is much more readable for the visitor.
