Mudras

At left is a representation of a Mudra, or sign of power, used in the Buddhist and Hindu religions. Each hand position represents a different spiritual truth; they are used during meditation, on statuary, and in sacred dance, often in conjunction with asanas, or body-postures.
There are 108 standard mudras used in Tantric ritual. Some of the better known mudras include the abhaya or “no fear” gesture, the dhyana or “meditation” mudra, and the Vitarka mudra, which resembles the christogram.
Such gestures are not exclusive to eastern religions; hand gestures with spiritual meaning are found in many religions.
Mudras in detail

Hindu deity Shiva making abhaya gesture