The word Upanishad is the name of a given subject matter, self-knowledge, just as the words geography and biology are names denoting particular subject matters. Thus, the meaning of the word Upanishad is self-knowledge.

The word itself is made up of two prefixes (upa and ni) and a word, sat or sad, from the root sad. This root has a three-fold meaning: wearing out (visaranam); putting an end to (avasadanam); and reaching or knowing (gamanam).

The word sat is the agent of the action indicated by its root and, therefore, means that which wears out, puts an end to, and makes you reach or know. Since the root sad has these three meanings, we need to see whether all three are applicable here or only one or two.

We find that all three apply, as evidenced by the word "sat" itself and the two prefixes upa and ni. The prefix ni means definiteness, that which is well ascertained. Therefore, knowledge is called ni. The prefix upa means that which is the nearest.

The nearest is oneself, "I," ätmä, and about this "I" there is confusion. What I have to know to remove this confusion is not away from myself. Because it is not other than myself, the word "nearest" is used for want of a better word.

The two prefixes together, then, upa-ni mean the definite knowledge of oneself. This knowledge wears out one's sorrows, meaning that it disintegrates them. They just fizzle out and they do not return, either in this life or any other. Self-knowledge removes them for good.

This is because the root cause for sorrow is ignorance about oneself. Self-knowledge removes the cause for sorrow so thoroughly that it puts an end to the product as well. Just as a tree cut down will not grow up again once its roots have been completely destroyed, sorrow will not recur once its cause, self-ignorance, has been removed by self-knowledge.

Ignorance of the fact that the self (ätmä) is the whole (Brahman) is the cause of all sorrow and this ignorance goes in the wake of knowledge. How does this happen? The knowledge of oneself enables one to recognize the fact of one being Brahma (Brahma gamayati). This recognition is the very knowledge itself. Self-knowledge, then, is the subject matter called Upanishad, found in the last portion of the Vedas.

The word Vedanta indicates the location of the subject matter, anta meaning end. Thus Vedanta is Upanishad. The word Upanishad itself reveals the desirability of pursuing this knowledge because its result is the end of sorrow. Self-knowledge is something that can be gained - and to do so requires a means of knowledge.

This means of knowledge is Vedanta, the end portion of the Vedas, whose subject matter is Upanishad, self-knowledge. The subject matter itself becomes the name of the Vedanta textbooks - the Upanishads. The plural is used because there are four Vedas and, therefore, four antas or endings. Collectively, they are referred to as Upanishad, but, with reference to the subject matter, there is only one.

There is no plural; there is only Upanishad. The Upanishads are in the form of various dialogues and each dialogue is called Upanishad, the subject matter being the same. Because the subject matter is the same, each book is also called Upanishad, after its subject matter, just as a book about American history bears the title "American History."

Here, too, a book about self-knowledge is called Self-knowledge, the meaning of Upanishad. Because there are many teacher-student dialogues, there are many Upanishads. To distinguish one from the other, a qualifying word precedes the word Upanishad in each title.

Thus we have isopanishad, kenopanishad, prashnopanishad, kathopanishad, mundakopanishad, mändukyopanishad, taittiriyopanishad, aiterayopanishad, chändogyopanishad, and brhadärany-akopanishad, among others. Modern academicians have identified the ten Upanishads cited above as major Upanishads only because Sankara wrote commentaries on them. Because the subject matter is the same, commentaries are not required for the others.

Sankara thought that the study of these ten alone would enable the student to understand the subject matter. Therefore, these ten became known as major Upanishads and the rest are referred to as minor. The words major and minor are in no way intended to reflect on the quality of the Upanishads themselves, but merely serve to indicate whether Sankara wrote commentaries on them or not.