Sanskrit is the primary liturgical language of Hinduism, a philosophical language in Hinduism, Buddhism, and Jainism, and a scholarly literary language that was in use as a lingua franca in the Indian cultural zone.
Hayden Panettiere has a Sanskrit Hindi tattoo on her right arm. I guess it is supposed to be जय गुरुदेव ॐ jay guru dev om, the mantra in The Beatles' "Across the Universe". It's not the nicest looking Devanagari, in my opinion. Also the रु looks weird.