Japa (Sanskrit: जप) is the meditative repetition of a mantra or a divine name. It is a contemplative practice that holds an important place in Hindu traditions, and is also found in Jainism, Sikhism and Buddhism, with parallels in several other religious traditions across the world.
The practice may take different forms depending on context and the practitioner's inclination. Japa may be performed while seated in a meditation posture, while engaged in other daily activities, or as part of formal worship conducted in group settings. In each setting, the central element remains the focused, repeated utterance or remembrance of the chosen mantra or name.
The mantra or divine name may be spoken softly, voiced loudly enough for the practitioner alone to hear, or recited silently within the practitioner's mind. These variations allow the practice to be adapted to differing temperaments, circumstances and stages of spiritual discipline within the traditions in which it is observed.
Adapted from the English Wikipedia article on Japa.