大般涅槃經義記 6.110

6.110

云何第一亦名為道？解有三義：一體義虛通即名為道；二約人分別，凡時實義，據聖望之，體無壅障即名為道；三約修分別，凡時實義，從緣顯了說之為道，亦名菩提及與涅槃，義皆同爾。

Why is the ultimate [truth] also called "the Path"? There are three explanations of its meaning: First, the meaning of its essence being unhindered and open is called "the Path." Second, distinguishing in terms of persons, the real meaning at the time of an ordinary person, viewed from the perspective of a noble one, has an essence free from obstruction and blockage, and is thus called "the Path." Third, distinguishing in terms of cultivation, the real meaning at the time of an ordinary person is revealed and made clear through conditions, which is called "the Path," and is also called bodhi and nirvāṇa; their meanings are all identical in this way.