Google rolled out last December something horrible called Google Dictionary, which it made the default dictionary for users of the Google Search engine in the English language. But now Google is suddenly doing dictionary definitions right!
Before last December, Google Searches offered a "definition" link in the upper right corner of the page. Clicking the link took you to the Answers.com definition for that word. That approach wasn't ideal, but not horrible, either.
In December, Google changed the default to take you to a definition from something new called Google Dictionary, which was really just a crappy English-as-a-second-language dictionary called the Collins COBUILD Advanced Learner's English Dictionary. (OK, it's a good dictionary for its purpose, which is to help foreign-language speakers learn English, but a lousy dictionary for those of us who already speak English and want nuanced, high-quality definitions.)
Suddenly, Google has fixed the whole mess. Now, when you search for a word via Google Search, Google uses something called "implicit triggering" to simply display word definitions without you having to explicitly indicate that you want a definition. Common words Google assumes you already know are not accompanied by a definition. But fancy and obscure words are, apparently. It's not clear how this decision-making process works, but it seems to work pretty well.
The definition shown appears to be an updated or improved version of the old Google Dictionary definition, plus pronunciations and parts of speech. Best of all, that information is accompanied by direct links to four dictionaries: Dictionary.com, Answers.com, Merriam-Webster (a standard for journalists) and The Free Dictionary. Of course, the links take you to the definition, not just the dictionary.
While the switch to a "learner's dictionary" in December seemed like a step backward for the cause of better English, the new, automatically displayed definition and links to four dictionary choices seems like two steps forward. By automatically displaying a dictionary entry for many words, Google will be teaching millions of people every day what the real definitions of those words are -- even people too lazy to look words up. And by providing four easy-to-click dictionary choices, Google will constantly advertise the existence of resources for better understanding words.