首楞嚴義疏注經 5.301

5.301

孫陀羅難陀，此云艶喜，兼妻得名，是佛親弟。前作數息，即約根說，今約觀識，緣鼻端白以駐其心，令不散動。

Sundarananda is translated here as 'Charming Joy', named in combination with his wife; he was the Buddha's younger brother. Earlier, counting the breath was spoken of with reference to the faculties; now it is spoken of with reference to contemplating consciousness, taking the whiteness at the tip of the nose as an object in order to anchor the mind and prevent it from scattering.