English

Noun

co-uncle ‎(plural co-uncles)

1. of a man, an uncle of one's niece or nephew who is not one's brother; a co-brother-in-law as common uncle to the children of two men's married siblings.
   • 1975, Elizabeth Rawson, Cicero: a portrait, page 195:

     Cicero continued however to write anxiously to Atticus, his co-uncle, about the young man's remarkable gifts and unsatisfactory character.
     [Cicero's younger brother married Atticus's sister, and the couple had a son Quintus; Cicero and Atticus were thus co-uncles to Quintus, the nephew they had in common]

2. a man's brother, as uncle in common to the children of a third sibling

   My nephew came up for the summer with my brother and co-uncle George.

Synonyms

• co-brother-in-law (relative to the married siblings rather than to the children; however, this term generally refers to a different relationship, that of two men who marry sisters)

Coordinate terms

• co-aunt

Related terms

• co-grandfather