[Buddha-l] Sanskrit puzzle

[Jayarava]

At the beginning of the Karaṇḍa-mudrā-dhāraṇī (T19, No. 1022A) are the words namastryadhvikanāṃ sarva tathāgatānāṁ. The word tryadhvikānāṃ occurs in a mantra in the Mahāvairocana Abhisaṃbodhi Tantra (p. 398 of Hodge's translation).

I've been puzzling over what to make of tryadhvikanāṃ? (possibly tryadhvikānāṃ) Is is tri + adhvika, and if so what can adhvika mean? - it's not in the MW dictionary. 

There's every possibility that the Chinese version is corrupt, but the fact that the same word occurs in a Tibetan translation makes it seem likely to be an actual word.

Any Sanskritists with a few spare minutes able to put me out of my misery?

Thanks
Jayarava