The Shin meikai kokugo jiten (新明解国語辞典, "New clear-understanding Japanese dictionary"), commonly called the Shinmeikai or affectionately the Shinkai-san (新解さん, "Mr/Ms Shinkai", with the personal suffix -san さん), is a popular Japanese dictionary published by Sanseidō.

They also publish the analogous Sanseido Kokugo Jiten dictionary, a lexicographical sister that shares several of the same editors.

This Japanese language reference work has frequently undergone revisions and republications.

The first two editions were called the Meikai kokugo jiten (明解国語辞典, "Clear-understanding Japanese dictionary"), and the six subsequent ones were published under the current Shin "New" name.

Following the death of Yamada Tadao, the Shin meikai kokugo jiten acquired a certain notoriety in Japan after the publication of the humorous bestsellers by Akasegawa Genpei (1996, "Mysteries of the Shinkai-san") and Suzuki Makiko (1998, "How to read the Shinkai-san").