noun
large encyclopedia
Refers to a comprehensive, multi-volume encyclopedia, often contrasted with smaller or single-volume reference works.
この図書館には大百科事典が揃っている。
This library has a full set of large encyclopedias.
A general encyclopedia, not necessarily large or multi-volume. 大百科事典 emphasizes a particularly extensive or comprehensive edition.
Compound of 大 (large) + 百科事典 (encyclopedia). The exact historical derivation is uncertain, but the term follows a common pattern for naming comprehensive reference works.