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彼女は私の姉妹です。
She is my sister.
Two or more female siblings, especially sisters who are close in age.
私には三人の姉妹がいます。
I have three sisters.
姉妹校は友好関係にあります。
The sister schools have a friendly relationship.
Can also refer to female siblings in a broader sense, including half-sisters or step-sisters.
'姉妹' specifically refers to female siblings. For male siblings, use '兄弟'.
Combination of 姉 (older sister) and 妹 (younger sister), referring to female siblings.
In business or organizational contexts, '姉妹' can refer to entities with a close relationship, such as sister companies or sister schools.