Encyclopedia Americana is a general encyclopedia written in American English. It was the first general encyclopedia of any magnitude to be published in North America. With Collier's Encyclopedia and Encyclopædia Britannica, Encyclopedia Americana became one of the three major and large English-language general encyclopedias; the three were sometimes collectively called "the ABCs of encyclopedias". Following the acquisition of Grolier in 2000, the encyclopedia has been produced by Scholastic.

An encyclopedia or encyclopaedia is a reference work or compendium providing summaries of knowledge, either general or special, in a particular field or discipline. Encyclopedias are divided into articles or entries that are arranged alphabetically by article name or by thematic categories, or else are hyperlinked and searchable. Encyclopedia entries are longer and more detailed than those in most dictionaries. Generally speaking, encyclopedia articles focus on factual information concerning the subject named in the article's title; this is unlike dictionary entries, which focus on linguistic information about words, such as their etymology, meaning, pronunciation, use, and grammatical forms.