You can use sister to describe something that is of the same type or is connected in some way to another thing you have mentioned. For example, if a company has a sister company, they are connected.
the International Monetary Fund and its sister organization, the World Bank.
国际货币基金组织和它的姐妹机构,世界银行。
sisters
Your sister is a girl or woman who has the same parents as you.
His sister Sarah helped him.
他姐姐萨拉帮助了他。
Vanessa Bell, the sister of Virginia Woolf.
弗吉尼亚·伍尔夫的姐姐瓦内莎·贝尔。
Sister is a title given to a woman who belongs to a religious community.
Sister Francesca entered the chapel.
弗朗西丝卡修女走进小教堂。
You can describe a woman as your sister if you feel a connection with her, for example, because she belongs to the same race, religion, country, or profession.
Modern woman has been freed from many of the duties that befell her sisters in times past.
现代女性已从压在旧时代姐妹们身上的许多责任中解放出来了。