Matsya Purana — Manvantaras
धर्मेति धारणे धातुर् महत्त्वे चैव उच्यते आधारणे महत्त्वे वा धर्मः स तु निरुच्यते //
dharmeti dhāraṇe dhātur mahattve caiva ucyate ādhāraṇe mahattve vā dharmaḥ sa tu nirucyate //
The verbal root (dhātu) behind the word “dharma” is said to convey the sense of “upholding/maintaining,” and also that of “greatness.” Thus dharma is explained as that which supports and sustains, and as that which is great in value and authority.
This verse does not discuss pralaya directly; it defines dharma as the principle that ‘upholds’ and is ‘great/authoritative’, a foundation for right order even across cycles of creation and dissolution.
By defining dharma as what upholds and supports, the verse frames royal and household duties as stabilizing society—protecting, sustaining, and maintaining order—because such sustaining action is itself ‘dharma’.
No direct Vāstu or ritual rule is stated, but the key idea—‘that which supports/bears’—aligns conceptually with Vāstu foundations and ritual order: correct practice is what ‘upholds’ sacred and social structures.