An encyclopedia — a large reference work that summarizes facts and concepts on a wide range of topics, arranged by entries.
図書館で百科事典を引いて、その歴史的事実を確認した。
I looked it up in an encyclopedia at the library to verify the historical fact.
子供向けの百科事典は図や写真が多くて分かりやすい。
Children's encyclopedias are easy to understand because they have many illustrations and photos.