Purāṇas · c. 3rd-5th c. CE (Matsya/Vāyu/Brahmāṇḍa/Viṣṇu); Bhāgavata c. 9th-10th c. CE
यथा मेढीस्तम्भ आक्रमणपशव: संयोजितास्त्रिभिस्त्रिभि: सवनैर्यथास्थानं मण्डलानि चरन्त्येवं भगणा ग्रहादय एतस्मिन्नन्तर्बहिर्योगेन कालचक्र आयोजिता ध्रुवमेवावलम्ब्य ... ॥ ३ ॥
Just as oxes, fastened to a post fixed in the centre of a threshing floor, leaving their own station, go round at shorter, middle or longer distances, — similarly fixed on the inside and outside of the circle of time, stars and planets exist, supporting themselves, on Dhruva. — J.M. Sanyal (1930s; public domain); cf. Wilson on VP 2.7.10: 'Dhruva (the pole-star), the pivot or axis of the whole planetary circle.'
A technical term for the pole, built on a vivid agricultural image: as oxen tied to a central post tread out grain in circles, so the stars circle Dhruva. Bhāgavata 5.23.3 develops the simile at length (meḍhīstambha, 'the post', with the ākramaṇa-paśavaḥ, treading cattle); the Matsya/Brahmāṇḍa/Vāyu group uses meḍhībhūta as an epithet of Dhruva directly.
Bhāgavata Purāṇa 5.23.3; Matsya Purāṇa 125.5 and 127.27; Brahmāṇḍa Purāṇa 1,22.6 and 1,23.106; Vāyu Purāṇa 52.97; cf. Viṣṇu Purāṇa 2.7.10 · text · translation