noun

• (countable) A group with a common interest.
  "First the cell, then combinations of cells, then combinations of combinations, then more and more complex combinations, till the body of man is reached, where endless confraternities of cells, all with different functions, working to build and sustain different organs, […]"
• (countable) A religious fraternity or brotherhood.
  "[…] in the later Middle Ages, in an urban complex, Carthusians and Benedictines would have existed alongside friars and beguines (and their southern counterparts) and possibly a Jewish community, […] many others committed to a confraternity or to special ascetic exercises […]"
• (uncountable) Brotherly friendship.
  "[Napoleon's] coronation as Emperor had been followed immediately by the great battle of Austerlitz, which had prostrated Austria at his feet, and reduced the Czar of Russia to so humiliating a condition as ended in the total disruption of his confraternity with the Germanic powers."