We already know that if Google thinks it can answer your search query effectively, it will highlight that result separately to actual site results. Google has increasingly placed those standalone results in what it calls 'OneBoxes', and those are now appearing in many mobile search results as well.
Searching for 'time london' has long given the current local time in the UK capital, but these days Google highlights that result more clearly using a OneBox. The same thing happens if you search for word definitions. Increasingly that's the case on mobile devices as well, as Google Operating System points out.
(Notice what a terrible definition that is, by the way.)
As with most Google rollouts, this is a gradual change: there's no evidence of it on my BlackBerry, for instance.
Google's Card-Style OneBoxes [Google Operating System]