成唯識論演祕 2.173

2.173

依止名身通諸根矣，而身根勝得總身名，餘立別稱。

The body as that which is relied upon applies generally to all sense faculties, yet because the tactile faculty (kāyendriya) is superior, it obtains the general name of 'body', while the rest are given distinct designations.