You've been om-ing your way through yoga class for years, but have you ever wondered what the mantra really means? According to the Yajur-Veda, one of the earliest sacred texts of the yoga tradition, om represents the entire universe -- past, present, and future. The sound is actually a combination of four parts: a ("ah"), or wakefulness; u ("oh"), the dream state; m ("mmm"), the quietness of deep, dreamless sleep; and the silence that follows, which represents pure consciousness.

As yogis will attest, the vibrations of om help settle the mind in a profound way. But don't wait until your next hatha class to say it. Use it whenever you need a quick infusion of calm.