Definitions of "more 20,000 terms ... [and] more than 6,000 stunning illustrations of a wide variety of objects from all aspects of life." Also includes audio clips of pronunciations. Searchable, or browsable by topics: astronomy, earth, plants, animals, humans, food, housing, clothing, arts and architecture, communications, transportation and machinery, energy, science, society, and sports and games. From Merriam-Webster. Note: may not work properly in all browsers.