The Supreme Vyūha
Vāsudeva ('son of Vasudeva' or, etymologically, 'He who dwells in all beings') is the supreme Vyūha — the highest level of divine manifestation in the Pañcarātra system, from which the other three Vyūhas emanate. He embodies all six ṣaḍguṇas (divine qualities) simultaneously and completely: jñāna, bala, aiśvarya, śakti, vīrya, and tejas.
Vāsudeva as Brahman
In Pañcarātra theology, 'Vāsudeva' is essentially synonymous with Brahman/Paramātman at the Vyūha level. The name appears in the Bhagavad Gītā: vāsudevaḥ sarvam iti — 'All is Vāsudeva.' The entire universe, all beings, and all activities are understood to be within Vāsudeva. This is a Pañcarātra expression of the Vishishtadvaita doctrine that Brahman is the self of all.
Name Derivation
The name Vāsudeva has two traditional etymologies: (1) Vāsu (Kṛṣṇa's father) + deva (son of) — the historical name of Kṛṣṇa as son of Vasudeva; (2) more theologically, vāsa (abides/dwells) + deva (Lord) — 'the Lord who dwells within all' — giving the philosophical meaning of the antaryāmin, the inner self of all beings.
Relationship to Kṛṣṇa
In practice, the Vyūha Vāsudeva and the historical Kṛṣṇa-Vāsudeva merge in Sri Vaishnava devotion: Kṛṣṇa is not merely a historical avatāra but the supreme Brahman in His approachable, loving, personal form. The name Vāsudeva carries the fullness of both the cosmic and intimate aspects.