© Writings of Sri Aurobindo and the Mother are the copyright of the Sri Aurobindo Ashram Trust, Pondicherry, India.

You have referred to Sri Aurobindo's Gayatri Mantra. Could you please provide word by word meaning of Sri Aurobindo's Gayatri Mantra. I have seen the English translation of the complete Mantra, however, I want to understand meaning of each of Sanskrit word, so that when I chant, the meaning remains at the back of my mind.

This might help
http://cdbaby.com/cd/arunamin

Mantras Eternal by Arun Amin

I have browsed to the referred site but could not locate. Once I had read word by word meaning, I do not know whether it was from Sri Aurobindo or some other Sadhak.

I have been chanting it in Sanskrit, however, without knowing the meaning of each word. Therefore, I am looking for the word by word meaning of Sri Aurobindo's Gayatri Mantra.

My Sanskrit is not perfect so I used http://vedabase.net/ dictionary.

Tat Savitur Varam Rupam Jyotih Parasya Dhimahi
Yannah Satyena Dipayet

Tat = That
Savitur = derived from Savitri (Creator)
Varam = most auspicious
Rupam = form
Jyotih = Light
Parasya = of the Lord (since para = Transcendental)
Dhimahi = meditate on (since Dhi = Intellect)
Yannah = by which (from yena http://vedabase.net/y/yena)
Satyena = Truth
Dipayet = illumine (dipa = light)

Let us meditate on the most auspicious form of Savitri, on the Light of the Supreme which shall illumine us with the Truth

The reason why Sri Aurobindo's Gayatri Mantra is different from the normal one is explained in M.P. Pandit's book "Sri Aurobindo and his Yoga" pp 106-107. You can find the relevant pages on http://books.google.com. Here I paraphrase the text

The Gayatri Mantra is addressed to the Sun of Spiritual Truth at the head of Creatiion. This is not the Sun around which the Earth revolves. That is why the Sun is called Savitri and not Surya.

The ordinary Gayatri Mantra illuminates only the mind
whereas Sri Aurobindo's modification is aimed at supramentalisation.

In Their Light,

Sri Aurobindo:

If one has faith and openness that is enough. Besides there are two kinds of understanding—understanding by the intellect and understanding in the consciousness. It is good to have the former if it is accurate, but it is not indispensable. Understanding by the consciousness comes if there is faith and openness, though it may come only gradually and through steps of experience. But I have seen people without education or intellectuality understand in this way perfectly well the course of the yoga in themselves, while intellectual men make big mistakes, e.g. take a neutral mental quietude for the spiritual peace and refuse to come out of it in order to go farther.

It is necessary to curb the mind's impatience a little. Knowledge is progressive—if it tries to leap up to the top at once, it may make a hasty construction which it will have afterwards to undo. The knowledge and experience must come by degrees and step by step.

Corresponding lines from Savitri which lay out the definitive way of entering into spirit of Savitri:

"This Light comes not by struggle or by thought;
In the mind’s silence the Transcendent acts
And the hushed heart hears the unuttered Word.
A vast surrender was his only strength.
A Power that lives upon the heights must act,
Bring into life’s closed room the Immortal’s air
And fill the finite with the Infinite."