The Sanskrit language is rich in words to communicate ideas about spiritual life, yoga, and God realization. This dictionary, appearing by installments in BACK TO GODHEAD, will focus upon the most important of these (and, occasionally, upon relevant English terms) and explain what they mean.

Absolute Truth. According to the Vedanta-sutra, which concisely states the essence of Vedic knowledge, the Absolute Truth is the source of everything, the ultimate cause of all causes. It is satyam param, the highest truth. The Srimad-Bhagavatamtells us that this supreme truth is pure, undivided knowledge and may be perceived in three features as Brahman (all-pervading, impersonal oneness), as Paramatma (the manifestation of God within the heart of every being), and as Bhagavan (the Supreme Personality of Godhead). These three are the same one truth, understood from increasingly advanced levels of realization. In the beginning one perceives the Absolute impersonally; with further advancement, one perceives the Supreme within one's own heart and the hearts of others; and with the highest realization, one perceives the Supreme Truth as the Supreme Personality of Godhead, who is complete in wealth, power, fame, beauty, knowledge, and renunciation. The Bhagavad-gita, Srimad-Bhagavatam, and other Vedic literatures identify this Supreme Personality of Godhead as Lord Sri Krsna.

Acarya. An acarya is a teacher specifically, a spiritual master who teaches not only by verbal instructions but by the way he acts in his own life. The Bhagavad-gita advises that one who wants to know truth should submissively approach a qualifiedacarya, surrender to him and serve him, and place before him sincere and relevant inquiries. The enlightened acarya can impart knowledge, for he is a seer of the truth. The Vedic literature emphatically says that unless one approaches such an acarya one cannot attain success in life. A qualified acarya, therefore, is one who has been enlightened in truth by his own acarya and who imparts the truth to others. The acarya should be spotless in character, and moreover it is essential that he be a devotee of the Supreme Lord. One who poses as an acarya but does not have an attitude of service to the Supreme Lord is useless.

Acintya-bhedabheda-tattva. This is the Vedanta philosophy explained by Sri Caitanya Mahaprabhu. In some places the Vedas say that all beings are one with God, and in others that God and all beings are different. This is a matter of considerable controversy among commentators on Vedanta philosophy. Sri Caitanya Mahaprabhu taught that both statements are simultaneously true. According to the Vedic literature, God is the ultimate source of multifarious kinds of energy. In this way He resembles the sun, which gives off energy in the form of heat and light. And just as the sun is inseparable from its rays, God is inseparable from His energies. God and His energies are therefore nondifferent. Yet simultaneously God and His energies are distinct. Although the sun and its rays are one, they are different also: while we on earth enjoy the rays of the sun, the fiery sun itself is millions of miles away. Similarly, although God is present everywhere by the manifestations of His energy, He simultaneously maintains His distinct personal identity, with His own name, form, qualities, abode, pastimes, and entourage. Since all living beings are manifestations of God's energy, God and the living beings are simultaneously different (bheda) and nondifferent (abheda). For the mundane mind this truth (tattva) is held to be inconceivable (acintya). The entire cosmic manifestation is also a manifestation of God's energy and is therefore simultaneously one with God and different from Him.

Acyuta. A name of Krsna meaning "the infallible one." Living beings are fallible because they can be overwhelmed by weakness or illusion. But these defects can never overcome the Supreme (for then weakness and illusion themselves would be supreme and the term "supreme" would be meaningless). The supreme or Krsna is therefore known as Acyuta. The material energy (the energy that illusions ordinary beings) is one of Krsna's energies and is therefore always under His supreme control. This is a distinction between the Lord and other living beings. Krsna is also called Acyuta because He never fails in His affection for His devotees.

Advaita. The word dvaita means "dual," and so advaita means "nondual." The material world is a world of dualities heat and cold, happiness and distress, up and down, black and white. According to the Vedic literature, however, the Absolute truth is free from all such material dualities: It is therefore called advaita.

Some philosophers, principally Sankara, have espoused the view that because the Absolute is free from dualities, it must be utterly impersonal and devoid of qualities. According to this view, which is called kevaladvaita or Advaita Vedanta, in the Absolute there can be no desires, thoughts, or perceptions, no sense of personal identity, no forms, qualities, or activity, but only undifferentiated spiritual oneness. This being so, whatever we now perceive is illusory.

A problem with this view, however, is that it leads one to ask, If nothing really exists but one undifferentiated Absolute Truth, where does the illusion of variety come from? How can illusion exist (or even appear to exist)? And if truth and illusion both exist, how can there be oneness? The exponents of Advaita Vedanta have yet to provide adequate answers to these questions.

Other Vedanta philosophers, however, have explained that although the Absolute Truth is one, the one truth spiritually manifests itself in unlimited diversity. That the Absolute is void of material characteristics does not mean that it must have no characteristics at all. The Vedic literature says, parasya saktir vividhaiva sruyate: the Absolute Truth is understood to have a varied multitude of energies. But because the Absolute is spiritual, these energies are ultimately spiritual too. In this way, there is oneness between the energies and their source. The varieties we perceive are not illusions; they are energies of the Absolute Truth, the Personality of Godhead, Krsna.

Our vision may be enlightened by truth or bewildered by illusion, according to our own desires, and this, too, is made possible by Krsna, through His varied energies. As parts of Krsna, we are naturally meant to serve Krsna, and when we do so we are in perfect oneness with the Absolute Truth. But when we separate ourselves from Krsna we plunge ourselves into illusion and duality. One attains liberation from illusion and duality when one surrenders to Krsna, accepting Him as advaita, "one without a second."