Weblio is a free integrated bilingual dictionary website and online encyclopedia for Japanese-speaking sites operated by the GRAS Group, Inc. (GRASグループ株式会社), formerly known as the Weblio Corporation (ウェブリオ株式会社).

[1] Weblio can perform a bulk search on a variety of dictionaries, encyclopedias and glossaries, and return results.

The dictionary facility includes Kenkyūsha's New Japanese-English Dictionary and 70 other Japanese–English and English–Japanese dictionaries with 4,160,000 English words and 4,730,000 Japanese words.

[2] As of January 20, 2016, a total of 665 dictionaries, encyclopedias and glossary sites can be searched in full.

[3] Beta testing began on December 12, 2005,[4] and the site began to formally provide services searching 11 different dictionaries and encyclopedias on January 25, the following year.