Śatapatha Brāhmaṇa ("of a hundred paths") 4.1.3.5

4.1.3.5

te devā abhyasṛjyanta | yathā vittiṃ vetsyamānā evaṃ sa yameko 'labhata sa ekadevatyo 'bhavadyaṃ dvau sa dvidevatyo yam bahavaḥ sa bahudevatyastadyadenam pātrairvyagṛhṇata tasmādgrahā nāma

The gods rushed thither,--as (those) eager to take possession of their property, so (it fared with) him (Vritra--Soma): what (part of him) one of them seized, that became an ekadevatya (graha, belonging to one deity), and what two of them, that became a dvidevatya, and what many (seized), that became a bahudevatya;--and because they caught him up each separately (vi-grah) by means of vessels, therefore (the libations) are called graha.