兄弟

brothers / younger brother / CL:個|个[ge4] / I, me (humble term used by men in public speech) / brotherly / fraternal

elder brother

younger brother / junior male / I (modest word in letter)

variant of 悌[ti4]

father's brother's sons / paternal male cousin

fraternity

internal disunity dissolves at the threat of an invasion from outside (idiom)

internecine strife (idiom); fighting among oneself

Brothers Karamazov by Dostoevsky 陀思妥耶夫斯基[Tuo2 si1 tuo3 ye1 fu1 si1 ji1]

all men are brothers

twin brothers

fellow apprentices / fellow students (male)

Warner Brothers

even with your own brother, keep clear accounts (idiom)

twin brothers

brothers and sisters / siblings