lSI keywords stands For Latent Semantic Indexing, LSI keyword shows the result of the phrases your search for. It shows the result of the top 10 pages of the phrase. It shows one word two word and three word phrase in results. It shows the semantically related keywords.It collects all the text from the result pages and shows the most used phrases on the page, and in front of them figure is given, means how many times a keyword is used.
I don't know what you're trying to say but you're mixing up different concepts. There is no search engine that uses LSI - the mapping of every word against the use of very other word is not something any search engine has the capacity for. What they do use is cruder forms of semantic matching. If you want to know how crude this can be - look at what gets matched to a broad match keyword in Adwords. If you want to know more about Google's synonym matching there's been a post on their official blog http://googleblog.blogspot.com/2010/01/helping-computers-understand-language.html