In Theravada Buddhist context, a samaneri (Pali: male: sāmaṇera) can be translated as novice nun. It literally means 'small samana', or small renunciate, where 'small' has the meaning of boy or girl.
In the Vinaya (monastic discipline), a woman under the age of 20 cannot ordain as a bhikkhuni, but can ordain as a samaneri. The male counterpart of the samaneri is the samanera. Samaneris and samaneras keep the 10 precepts as their code of behavior, and are devoted to the Buddhist religious life.
After a year or at the age of 20, a samaneri will be considered for the higher Bhikkhu or Bhikkhuni ordination (Pali: upasampada). Some monasteries will require people who want to ordain as a nun or monk to be a novice for a set period of time, as a period of preparation and familiarization.