A bhikkhu (Pali, Sanskrit: bhikṣu, Sinhala: භික්ෂුව) is an ordained male monastic ("monk") in Buddhism. Male and female monastics ("nun", bhikkhuni (Sanskrit bhikṣuṇī) are members of the Buddhist community. The lives of all Buddhist monastics are governed by a set of rules called the prātimokṣa or pātimokkha. Their lifestyles are shaped to support their spiritual practice: to live a simple and meditative life and attain nirvana. A person under the age of 20 cannot be ordained as a bhikkhu or bhikkhuni but can be ordained as a śrāmaṇera or śrāmaṇērī.