Bhagavatapurana 3.11.1

3.11.1

/0 maitreya uvāca
caramaḥ sad-viśeṣāṇām aneko 'saṃyutaḥ sadā /
paramāṇuḥ sa vijñeyo nṛṇām aikya-bhramo yataḥ //

Maitreya said:—That should be known as a Paramanu or an atom which is the last and the least particle of the parts into which a gross product may be divided, and which is not one, i.e., which has not attained to the state of being an effect, or being a group, which always remains uncombined with another. Only with reference to the accumulation of such particles or atoms do men have the illusory notion of an organic whole.