SB 2.10.11

tāsv avātsīt sva-sṛṣṭāsu
 sahasraṁ parivatsarān
tena nārāyaṇo nāma
 yad āpaḥ puruṣodbhavāḥ
Synonyms: 
tāsu — in that; avātsīt — resided; sva — own; sṛṣṭāsu — in the matter of creation; sahasram — one thousand; parivatsarān — years of His measurement; tena — for that reason; nārāyaṇaḥ — the Personality of Godhead named Nārāyaṇa; nāma — name; yat — because; āpaḥ — water; puruṣa-udbhavāḥ — emanated from the Supreme Person.
Translation: 
That Supreme Person is not impersonal and therefore is distinctively a nara, or person. Therefore the transcendental water created from the Supreme Nara is known as nāra. And because He lies down on that water, He is known as Nārāyaṇa.