Śatapatha Brāhmaṇa ("of a hundred paths") 1.3.5.1

1.3.5.1

indhe ha vā etadadhvaryuḥ | idhmenāgniṃ tasmādidhmo nāma samindhesāmidhenībhirhotā tasmātsāmidhenyo nāma

With the fire-wood (idhma, lighting material) the Adhvaryu lights (indh) the fire: hence it is called fire-wood. And with the kindling verses (sâmidhenî) the Hotri kindles (sam-indh, to make blaze): hence they are called kindling verses.