1. Eu·re·ka A city of northwest California on Humboldt Bay, an arm of the Pacific Ocean. Lumbering, fishing, and tourism are important to its economy. Population: 25,400. 2. eu·re·ka interj. Used to express triumph upon finding or discovering something. The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000 by Houghton Mifflin Company.… Continue reading Eureka! An Off-Beat Dream Leads to a Road Trip There