Easily define most any word or phrase with Definr. Touting an "incredibly fast" search and AJAX word completion box amidst a roomy white layout, Definr is a handy tool for those quick mental block "reassurances."

Definr is based on the ultra fast Ruby on Rails system with a MySQL database. It utilizes Princeton’s open WordNet 2.0. They cache the top 10,000 words to speed up the process even more. Their word completion server is seperate from the rest of their site to decrease any delay in response time. More detailed information can be found here. Definr stylishly joins its online reference buddies like Reference.com, Answers.com, and Google.

I usually use Google’s define feature. Searching, define: word, will actually find a definition for "word" from several different sources. Definr’s lookup via simple urls makes usage a breeze also. Simply visit, definr.com/word, to be wisked away to the knowledge that a word is actually a "unit of language that native speakers can identify."