Bhashya
स होवाच इतरः— हे गार्गि, यत् त्वयोक्तम् ‘ऊर्ध्वंदिवः’ इत्यादि, तत्सर्वम्— यत्सूत्रमाचक्षते— तत् सूत्रम्,
In plain words
Yājñavalkya answered her. Gārgī, he said, everything you just described — 'above the sky' and all the rest — that is exactly what the old teachers call the thread. That is the thread.
Close to the Sanskrit
He, the other one, said: O Gārgī, that which was said by you — 'above heaven' and so on — all that, which they call the thread, that is the thread.