n.
  - the relationship between brothers. 
▸a feeling of kinship and closeness.
 - an association or community of people with a common interest, religion, or trade. 
▸N. Amer. a trade union.
 
 
  Etymology
  ME: prob. from obs. brotherred (based on OE -ræden ‘condition, state’), assoc. with words ending in -hood and -head1.