This word has been used in the Upaniṣads in several senses. Just as a city, (pura = city) full of people and various goods, supplies the wants of the king, this body of several limbs and sense-organs, supplies the needs of Brahman who resides in it in the form of the jīva or the indi-vidual soul. Hence it is called ‘brahmapura’ or ‘the city of Brahman’ (vide Chāndogya Upaniṣad 8.1.1).
Sometimes the word is applied to the ‘lotus of the heart’ (hṛdayapuṇḍarīka—the psychic heart, where meditation is practised) since it ‘houses’ Brahman; i.e., Brahman is realised there by the practice of meditation on it, there. (vide Muṇḍaka Upaniṣad 2.2.7)