Google have made an aesthetic change to two features which were previously hidden underneath advanced search. Both the dictionary definition tool, and Google Reading level have now been integrated firmly into the sidebar. Reading level allowing users to refine their search based on the complexity of the material found in the results. Your results will then be displayed using an indicator for how difficult the material is to read. Selecting advanced reading level for example returns more university results and research, whereas a Basic search returns wikipedia entries and other simple definitions from around the web.
The dictionary performs a “define:” query automatically based on what you have searched, which many of you probably type manually in the search box at present to return results from.
Technically, both these features of Google search are complex to implement, and the move to highlight them makes complete sense, particularly if they are seeing low adoption levels amongst even power users.