プログレッシブ和英中辞典(第4版)の解説
きょうだい【兄弟】
〔男〕a brother；〔女〕a sister；〔男女を問わず〕 《文》 a sibling
兄弟の brotherly; sisterly
異母［父］兄弟
a half brother [sister]
乳兄弟
a foster brother [sister]
ご兄弟は何人ですか
How many brothers and sisters do you have?
僕は３人兄弟です
I have two brothers.（▼自分を含めない）
兄弟が２人で姉妹も２人です
I have two brothers and two sisters.
兄弟はいません
I don't have any brothers or sisters.（▼通例複数形）
兄弟は他人の始まり
Even brothers forget their bonds when there is a conflict of interest.
山田（三）兄弟
the (three) Yamada brothers
兄弟愛
brotherly love
兄弟喧嘩(げんか)
a quarrel between siblings
子供のころはよく兄弟げんかをしたものだ
I often quarreled with my brother [sister/brothers and sisters] when I was little.
兄弟殺し
fratricide
兄弟弟子
fellow disciples
兄弟分
a sworn brother