Bhikkhunī in the context of "Tonsure"

A nun is a woman who vows to dedicate her life to religious service and contemplation, typically living under vows of poverty, chastity, and obedience in the enclosure of a monastery or convent. The term is often used interchangeably with religious sisters who do take simple vows but live an active vocation of prayer and charitable work in the wider society.

In Christianity, nuns are found in the Catholic, Oriental Orthodox, Eastern Orthodox, Lutheran, and Anglican and some Presbyterian traditions, as well as other Christian denominations. In the Buddhist tradition, female monastics are known as Bhikkhuni, and take several additional vows compared to male monastics (bhikkhus). Nuns are most common in Mahayana Buddhism, but have more recently become more prevalent in other traditions.

Empress Kōken (born Abe, known as Empress Shōtoku during her second reign; 718–770) was the 46th and 48th monarch of Japan according to the traditional order of succession. She was born to Crown Prince Obito (the future Emperor Shōmu) and his consort Fujiwara Asukabehime; seeking to protect the bloodline of Prince Kusakabe, her father proclaimed her the first crown princess in Japanese history in 738. She became the Empress Regnant in 749, after her father retired to become a Buddhist monk. With the backing of her mother (now Dowager Empress Kōmyō) and her mother's nephew Fujiwara no Nakamaro, she was able to outmaneuver a largely hostile Daijō-kan (Council of State). Her father died in 756, having named a cousin unrelated to the Fujiwara as her heir; this outraged Fujiwara supporters, and Kōken replaced him with Prince Ōi, a close ally of her mother and Nakamaro. In 757, she headed off a conspiracy to overthrow her by Tachibana no Naramaro, and resigned the following year to serve as empress emerita (Daijō Tennō), while Ōi reigned as Emperor Junnin.

Nakamaro slowly consolidated his political power with the backing of dowager empress Kōmyō. After an illness, Kōken became close to a healer-monk named Dōkyō, who became one of her strongest allies, as well as potentially an intimate partner. After this, she became a bhikkhunī (Buddhist nun) and shaved her head. After her mother's death in 760, Kōken began to oppose Nakamaro. She proclaimed superiority over Emperor Junnin in state matters in 762, and allied with anti-Nakamaro leaders, including her childhood tutor Kibi no Makibi. In 764, political conflict grew violent after she attempted to take control of the royal seals; Nakamaro fought a brief rebellion against her, naming Prince Shioyaki as emperor, but both were captured and executed, and Kōken returned to the throne as Empress Shōtoku.

Sannyasa (Sanskrit: संन्यास, romanized: saṃnyāsa), sometimes spelled sanyasa, is the fourth stage within the Hindu system of four life stages known as ashramas, the first three being brahmacharya (celibate student), grihastha (householder) and vanaprastha (forest dweller, retired). Sannyasa is traditionally conceptualized for men or women in the last years of their life, but young brahmacharis have the choice to skip the householder and retirement stages, renounce worldly and materialistic pursuits and dedicate their lives to spiritual pursuits.

Sannyasa, a form of asceticism marked by renunciation of material desires and prejudices, is characterized by a state of uninterest in and detachment from material life, with the purpose of spending one's life in peaceful, spiritual pursuits. An individual in Sanyasa is known as a sannyasi (male) or sannyasini (female) in Hinduism. Sannyasa shares similarities with the Sadhu and Sadhvi traditions of Jain monasticism, and the sannyasi and sannyasini share similarity with the bhikkhus and bhikkhunis of Buddhism.

A bhikkhu (Pali: भिक्खु, Sanskrit: भिक्षु, romanized: bhikṣu) is an ordained male in Buddhist monasticism. Male, and female monastics (bhikkhunī), are members of the Sangha (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.

The Vinaya (Pali and Sanskrit: विनय) refers to numerous monastic rules and ethical precepts for fully ordained monks and nuns of Buddhist Sanghas (community of like-minded sramanas). These sets of ethical rules and guidelines developed over time during the Buddha's life. More broadly, the term also refers to the tradition of Buddhist ethical conduct. The term "Vinaya" also refers to a genre of Buddhist texts which contain these precepts and rules and discuss their application, along with various stories of how the rules arose and how they are to be applied. Various lists and sets of Vinaya precepts were codified and compiled after the Buddha's death in different Vinaya texts.

As one of the main components of the canonical Buddhist canons (Tripiṭakas), alongside the Sūtra and Abhidharma (Pāli: Abhidhamma), the Vinaya Piṭakas contains detailed prescriptions governing the behavior, conduct, and communal procedures of monks (bhikṣu) and nuns (bhikṣuṇī). These include rules of individual discipline (prātimokṣa), protocols for communal harmony, and guidelines for handling transgressions.