(n.) The act of fraternizing or uniting as brothers.

affiliation alignment alliance amalgamation association cahoots coadunation coalescence coalition collaboration colleagueship collegialism collegiality combination companionship company comradeship confederacy confederation confraternity consociation consolidation cooperation copartnership copartnery federation fellowship fifth-column activity fraternalism fraternity freemasonry fusion high treason hookup inclusion incorporation integration league lese majesty membership merger misprision of treason partaking participation partnership petty treason quislingism sedition sharing society sodality sorority tie-in tie-up treason unification union