The Gayatri Mantra is the most famous mantra of Hinduism.
Gayatri is actually the name for a Sanskrit poetical meter that contains three lines of eight syllables each. There are, therefore, many gayatri mantras, but this particular one is the oldest and most well known of all gayatri mantras. In Hinduism all Gods and Goddesses have a gayatri mantra associated with them. There is a gayatri for Ganesha, one for Shiva, one for Durga, one for Vishnu, one for Lakshmi, and so on. Most people are unaware of this fact and when Hindus talk about the gayatri mantra they mean this specific one, which is addressed to Savitri, the sun.
Om Bhur Bhuvah Svah
Bhargo Devasya Dhimahi
Dhiyo Yo Nah Pracodayat
– From the album The Essence
Meaning of Gayatri Mantra
Let us meditate on the light of the sun which represents God, and may our thoughts be inspired by that divine light.
* for a deeper translation, see here.
– Rigveda (iii /62/10)