仁王經疏 3.484

3.484

釋曰：第二、顯三勝也。此三統攝一切三昧，有大勝用，故名為王。《智度論》云「三昧王三昧」。

Explanation: Second, revealing the three excellences. These three comprehensively subsume all samādhis and possess vast, supreme functions; therefore, they are called 'kings'. The Da zhidu lun calls this 'the samādhirāja samādhi'.