Śatapatha Brāhmaṇa ("of a hundred paths") 8.3.3.5

8.3.3.5

mā canda iti | ayaṃ vai loko māyaṃ hi loko mita iva pramā canda ityantarikṣaloko vai pramāntarikṣaloko hyasmāllokātpramita iva pratimā canda ityasau vai lokaḥ pratimaiṣa hyantarikṣaloke pratimita ivāsrīvayaścanda ityannamasrīvayastadyadeṣu lokeṣvannaṃ tadasrīvayo 'tho yadebhyo lokebhyo 'nnaṃ sravati tadasrīvayo 'thāto niruktānyeva candāṃsyupadadhāti

[He lays down the right set, with, Vâg. S. XIV, 18], 'The metre Measure;'--the measure (mâ), doubtless, is this (terrestrial) world, for this world is, as it were, measured (mita);--'the metre Fore-measure!'--the fore-measure (pramâ), doubtless, is the air-world, for the air-world is, as it were, measured forward from this world;--'The metre Countermeasure,'--the counter-measure (pratimâ), doubtless, is yonder (heavenly) world, for yonder world is, as it were, counter-measured in the air;--'The metre Asrîvayas,'--'asrîvayas,' doubtless, is food: whatever food there is in these worlds that is 'asrîvayas.' Or, whatever food (anna) flows (sravati) from these worlds that is 'asrîvayas.' Hereafter, now, he puts down only defined metres.