A nondescript term pertaining to a member within a close group of friends, used by another within the same group. The term is somewhat endearing with a slight hint of teasing. It originally came from Shakespearean English, cited in the play King Lear. And while still showing the familiarity between the addresser and the addressee, the term was used in a more mocking sense in the Shakespearean language than it is today. Usually only used in conversations between males (no known usages to or between females).
(one nuncle) "What time is it, nuncles?"
(another nuncle) "Time to get a new fence."