Definition of ‘nun’

In the word analyses, ‘nun’ (bhikkhunī’ti)  is defined like this:

“She is:

• a nun because she lives on alms (bhikkhikā’ti bhikkhunī);
• a nun because she submits to wandering for almsfood (bhikkhācariyaṃ ajjhupagatāti bhikkhunī)
• a nun because she wears the patchwork cloth (bhinnapaṭadharāti bhikkhunī)
• a nun by common designation (samaññāya bhikkhunī);
• a nun by formal agreement (paṭiññāya bhikkhunī);
• a nun through being told “Come, nun!” (ehi bhikkhunīti bhikkhunī);
• a nun ordained by going to the three Refuges (tīhi saraṇagamanehi upasampannāti bhikkhunī).

"A nun

• is auspicious (bhadrā bhikkhunī);
• is the heartwood (sārā bhikkhunī);
• may be a Path-attainer (sekhā bhikkhunī);
• may be a Path-adept (asekhā bhikkhunī);
• is someone who was entitled to, and received ordination by a legitimate act of both Sanghas involving a motion and three invitations (samaggena ubhatosaṅghena ñatticatutthena kammena akuppena ṭhānārahena upasampannāti bhikkhunī).

"In conclusion:

• a nun who was entitled to, and received, ordination by a legitimate act of both Sanghas involving a motion and three invitations, such a person is what is intended as the meaning of the word ‘nun’
  (tatra yāyaṃ bhikkhunī samaggena ubhatosaṅghena ñatticatutthena kammena akuppena ṭhānārahena upasampannā ayaṃ imasmiṃ atthe adhippetā bhikkhunīti)” (Vin.4.214).