Wordnik (formerly Alphabeticall), seeks to provide information about all English words, and to give you a place where you can make your own opinions about words known.
In addition to definitions, wordnik provides:
An example sentence—even if we’ve only found one sentence for a word, we’ll show it to you. (And we’ll show you where the sentence came from, too!
Related words: not just synonyms and antonyms, but words that are used in the same contexts. (For instance, cheeseburger, milkshake, and doughnut are not synonyms, but they show up in the same kinds of sentences.)
Images tagged by our friends at Flickr: want to know what a “pout” looks like? We’ll show you.
Statistics: how rare is “tintinnabulation”?
An audio pronunciation—and you can record your own!
It was started by lexicographer Erin McKean and investors Roger McNamee and Steve Anderson.