American Heritage Dictionary
(1)
Century Dictionary
(2)
GNU Webster's 1913
(1)
WordNet
(2)
Elsewhere on the web
Despite its widespread reports, the brain mechanism underlying eureka is poorly understood.— innovations-report
The story goes that Darwin traveled to the Galapagos Islands in the Pacific Ocean and then, upon observing the giant tortoises and finches -- eureka!— Top Stories - Google News
All the possible precursor cards have been dealt ahead of Thursday's nominations, and in a year that offers fewer possibilities than most, all we can do is wait, shuffling and reshuffling the same predictions in vain hope of a 'eureka' moment.— In Contention
"That was when this got really interesting, it was a real 'eureka' moment."— HeraldNet.com Local, Sports, Business and Entertainment News
In that newspapers "report on business weekend" section, eureka: "A switch toward more profitable products, such as lines of credit, is helping the core operations churn out strong earnings" for the BMO.— rabble.ca - News for the rest of us

American Heritage Dictionary (1)
Century Dictionary (1)
Bubble size: how much this word was used in a year
Bubble height: used more or less than expected, vs. all uses evenly distributed
You can expect to see this word about twice a year.