Less than two months ago, Merriam-Webster announced that some of its references would be available via an API. Now, competitor Cambridge University Press has followed suit with the Cambridge Dictionaries Online API. Currently, Cambridge offers five dictionaries through an API (i.e. Cambridge Advanced Learner's Dictionary, Cambridge Dictionary of American English, Cambridge Business English Dictionary, Cambridge Learner's English-Turkish Dictionary, and Cambridge Leaner's Dictionary).
The Big Huge Thesaurus API provides a convenient interface for initiating a search based on an English word and retrieving related words and phrases. The Big Huge Thesaurus includes more than 145,000 english language words.
Nature Publishing Group (NPG), leading publisher of high impact scientific and medical information, has launched the OpenSearch API that provides an open, bibliographic search service for nature.com. The API grants developers access to over half a million research articles.