The Gayatri is a 24-syllable hymn from the Rig Veda (III, 62, 10). The phrase Om Bhoor Bhuvah Svah is generally added when the mantra is recited. The Sanskrit word Gayatri is formed by two words, ganat (or gayanath), which means "that which is sung," and trayate, which means "that which delivers."

In other words, the Gayatri is a song of deliverance. Gayatri is the most renowned mantra of the Vedas. It is addressed to the divine life-giver as supreme God, symbolized in Savitri, the Sun. For this reason this prayer is also called Savitri.
The words from the Gayatri can be interpreted as follows
Aum = Brahma ; bhoor = embodiment of vital spiritual energy(pran) ; bhuwah = destroyer of sufferings ; swaha = embodiment of happiness ; tat = that ; savitur = bright like sun ; varenyam = best choicest ; bhargo = destroyer of sins ; devasya = divine ; dheemahi = may imbibe ; dhiyo = intellect ; yo = who ; naha = our ; prachodayat = may inspire ;

O God! Thou art the giver of life,
The Remover of Pains and Sorrows,
the Bestower of Happiness
O Creator of the Universe,
may we receive Thy Supreme Sin - destroying light.
May Thou guide our intellect in the right - direction.

Its meaning is that "May the Almighty God illuminate our intellect to lead us along the righteous path". Gayatri mantra has been bestowed the greatest importance in Vedic dharma. This mantra has also been termed as Ved-Mata, the mother of the Vedas.

Meaning of Gayatri Mantra
Extracted from: "The Great Science and Philosophy of Gayatri" by Shree Ram Sharma Acharya, Shanti Kunj, Hardwaar, Uttar Pradesh, India

”Rishis selected the words of various Mantras and arranged them so that they not only convey meaning but also create specific power through their utterance. Gayatri Mantra inspires wisdom. Its meaning is that "May the Almighty God illuminate our intellect to lead us along the righteous path". All the problems of a person are solved if he/she is endowed with the gift of righteous wisdom. Once endowed with far-sighted wisdom, a man is neither entangled in calamity nor does he tread the wrong path. A wise man finds solution to all outstanding problems. Only those persons who do not think correctly find difficulty and take wrong steps due to foolishness. Chanting of Gayatri Mantra removes this deficiency. The teachings and powers incorporated in the Gayatri Mantra fulfill this purpose. Righteous wisdom starts emerging soon after Jap (recitation) of this Mantra is performed.”