shad, besides being the recognised title of certain philosophical treatises, occurs also in the sense of doctrine and of secret doctrine, and that it seems to have assumed this meaning from having been used originally in the sense of session or assembly in which one or more pupils receive instruction from a teacher.
Thus we find the word upanishad used in the Upanishads themselves in the following meanings:
1. Secret or esoteric explanation, whether true or false.
2. Knowledge derived from such explanation.
3. Special rules or observances incumbent on those who have received such knowledge.
4. Title of the books containing such knowledge.
I. Ait. Âr. III, 1, 6, 3. 'For this Upanishad, i.e. in order to obtain the information about the true meaning of Samhitâ, Târukshya served as a cowherd for a whole year.'
Taitt. Up. I, 3. 4 'We shall now explain the Upanishad of the Samhita.'
Ait. Âr. III, 2, 5, 1. 'Next follows this Upanishad of the whole speech. True, all these are Upanishads of the whole speech, but this they declare especially.'
Talav. Up. IV, 7. 'As you have asked me to tell you the Upanishad, the Upanishad has now been told you. We have told you the Brâhmî Upanishad,' i.e. the true meaning of Brahman.
In the Khând. Up. III, 11, 3, after the meaning of Brahman has been explained, the text says: 'To him who thus knows this Brahma upanishad (the secret doctrine of Brahman) the sun does not rise and does not set.' In the next paragraph brahma itself is used, meaning either Brahman as the object taught in the Upanishad, or, by a slight change of meaning, the Upanishad itself.
Khând. Up. I, 13, 4. 'Speech yields its milk to him who knows this Upanishad (secret doctrine) of the Sâmans in this wise.'
Khând. Up. VIII, 8, 4. When Indra and Virokana had both misunderstood the teaching of Pragâpati, he says: 'They both go away without having perceived and without having known the Self, and whoever of these two, whether
