In the last update Google said on its official page on google+, there is a new tool called "square definitions and meanings", and to use this new features just write a word in the search box to know its meaning or definition, and it will show you in the bottom a box contains the full meaning of the word, and when you click on the "More" google will show you more informationq about the real origin of the word, with a further list of it synonyms.
Google go further than we expect with this property, it's the matter of understanding the meaning of the word, away from the pattern matching words to search only, google now understand what users looking for.
this tool stay in its early stages, however, is extremely helpful at the moment, which makes Google removes ambiguity for more keywords.