Bhikkhu

A Bhikkhu (Pāli) or Bhikṣu (Sanskrit) is an ordained male Buddhist monastic. A female monastic is called a Bhikkhuni (Skt: Bhikṣuṇī) Nepali: भिक्षुणी). The life of Bhikkhus and Bhikkhunis is governed by a set of rules called the patimokkha within the vinaya's framework of monastic discipline. Their lifestyle is shaped to support their spiritual practice, to live a simple and meditative life, and attain Nirvana. In the Vinaya monastic discipline, a man under the age of 20 cannot ordain as a bhikkhu but can ordain as a samanera (เณร); the female counterpart is samaneri.

Read more about Bhikkhu:  Introduction, Monks in Japan