The Lord answers. Brahman refers to the akṣara—that which does not get destroyed, that which is eternal and supreme. The śruti says etad vai tad akṣaram gārgi brāhmaṇā abhivadanti: the knowers of Brahman call the Supreme Lord (tad) the indestructible (akṣaram). [Note: In verse 21 Viśvanatha says that the akṣara is Nārāyaṇa.] (Bṛhad Āraṇyaka Upaniṣad 3.8.8) Svabhāva means “that which produces one’s self (svaṁ bhāvayati), from imposition of a body.” In other words, it means the jīva, since it creates the body. The jīva is called adhyātma. Or the meaning of svabhāva can be “that which causes one to attain the Paramātmā (sva meaning the Lord in this case). In this case adhyātma refers to the purified jīva, since only the pure jīva is qualified to attain Paramātmā. The word karma refers to transmigration (visarga) of the jīva, the creation of bodies (bhāva) through the material elements (bhūta). It is called karma because it is produced from actions.

Being asked, the Lord replies to these seven questions one by one. Akṣaram means that which does not perish. I call the jīvātmā, which does not perish, distinct from the body (paramam), brahma. The śruti states that jīva is called brahma and akṣaraṁ: avyaktam akṣare līyate’kṣaraṁ tamasi līyate tama ekībhavati parasminn Avyakta (subtle state of prakṛti) merges into aksara (aggregate of the jīvas). Aksara merges into tamas (subtle state of prakṛti with jīva). Tamas becomes one with the Supreme Lord. [Note: Akṣara cannot refer to the Supreme Lord in this verse, since akṣaraṁ merges into tamas and tamas merges into the Lord.] Subāla Upaniṣad 1 vijṣānaṁ brahma ced veda If one knows the ātmā, called brahman, as vijṣāna, one does not become bewildered. [Note: See Baladeva’s commentary on Vedānta Sūtra 1.1.12 for further explanation. When food, prāṇa, mind, and vijṣāna are called brahman, brahman means jīva. When bliss is called brahman it refers to the Supreme Lord.] Taittirīya Upaniṣad 2.5 I refer to the svabhāva as adhyātma. Svabhāva is that substance (bhāva means padārtha) intimately connected to the jīva (sva)—the impressions held in the subtle elements which accompany the jīva birth after birth. Because the impressions are closely related to the ātmā, described as such in the paṣcāgni vidyā of the Chāndogya Upaniṣad, they are called svabhāva. This svabhāva is what I call adhyātma, that which governs the body. That creative force (visarga) which gives rise (udbhava kara) to the bodies (bhāva) of men and others by combination of the subtle elements (bhūta) with the gross elements (bhūta) is called karma. By performance of jyotistoma sacrifice one goes to svarga and in the body of a devatā one enjoys. The remnants coming from pious actions, which are similar to the remnants of ghee gathered in a pot for enjoyment, but which eventually are depleted, appear on this earth for giving the gross body of human or other form to the jīva. This is what I call karma. In the Chāndogya Upaniṣad, Chapter 5, it is described that five offerings of faith, god of the moon, rain, food and semen are offered into the five fires of heaven, the god of rain, earth, man and woman. The meaning is this. The jīva following the Vedas in this world offers yogurt and other items with faith. Because they are made of the five elements, those offerings with faith take the form of the five elements, and particularly water. [Note: At the beginning of the fifth chapter of the Upaniṣad, it was asked, “Do you know how the fifth oblation in the form of water becomes man?” Water represents all the elements but is mentioned because water makes up most of the human body. It is said that water means the elements water, earth and fire in subtle form as senses, as these accompany the jīva in all his bodies, and act as a base for the prāṇas and mind which also go with the jīva. These rudimentary elements follow the jīva and assist in producing his gross bodies, as well as carrying previous impressions and karmic reactions.] Because of offering water with faith, it becomes an oblation of faith. This envelops the jīva and goes with him. When the person dies, the devas presiding over the senses offer the oblations of faith to the fire called heaven. That means they lead the jīva to heaven. Those offerings transform into a heavenly body called Somarāja, King of the Moon. In that body, the jīva enjoys the results of his actions. At the end of enjoyment, the offerings along with the jīva are offered by the devas into the fire of Parjanya, God of Rain, and become rain. That rain along with the jīva is offered by the devas into the fire called earth and become food such as rice. The rice offerings along with the jīva are offered into the fire called man, and then become semen. The semen along with the jīva is offered into the fire called woman, and becomes an embryo, and transforms into man. The cause of such states, the consequence of actions, the residue from actions, is called karma. Thus the writer of the Sūtras has said tad-antara-pratipattau: in going to another body, the jīva takes the subtle elements. [Note: This description and the quotation from the Vedānta Sūtra is given to show that the jīva assumes a gross body by combination of subtle and gross elements (bhūta), which are mentioned in the verse: bhūta bhāva udbhāva kara, This particular sūtra refers to the description of the five oblations mentioned Chāndogya Upaniṣad and Bṛhad Āraṇyaka Upaniṣad.] (Vedānta Sūtra 3.1.1)

Srila Prabhupada explains in detail, according to the Chandogya Upanisad, about the meaning of karma. It means specifically, technically, according to the Purport: 'Karma means after one performs yajna or sacrifice, he goes to the heavenly planets. Then just before the 'punya' or good karma that is holding him up in the heavenly planets, expires, when there is just a little bit left, he comes down in the form of rain and that rain is absorbed to make the grains grow and the grains are eaten and become semen and the semen gives origin to a child gradually ‑ that is karma ‑ that action which develops material body for a soul when he descends from the heavenly planets. That specifically is what Krsna explains as karma. This body is composed of karma.