ひゃっかじてん
ひゃっかじてん · hyakkajiten · JLPT N2 · noun
encyclopedia
📚 百科 (hundred fields) + 事典 (reference dictionary) = a dictionary of a hundred fields
百 means hundred and 科 means field or subject, so 百科 stands for all fields of knowledge. Add 事典, a reference book, and you get an encyclopedia.