big sister

American  

noun

1. an elder sister.

2. (sometimes initial capital letters) a woman who individually or as a member of an organized group undertakes to sponsor or assist a girl in need of help or guidance.

3. (sometimes initial capital letters) a young woman in the junior or senior class in college who advises a young woman in the freshman class on studies, social activities, etc., often as a part of a sorority program.

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Example Sentences

"I loved her to bits, she was my big sister who did everything for all of us."

From BBC • Mar. 10, 2026

What she found was that the relationship went beyond business; she sees her agent as part negotiator, part therapist, part big sister.

From The Wall Street Journal • Mar. 4, 2026

In this week’s episode of The Envelope podcast, the “Sentimental Value” star reflects on growing up onscreen and following in big sister Dakota Fanning’s footsteps.

From Los Angeles Times • Feb. 26, 2026

Affectionately called "big sister" by her teammates, she is leading a new generation of Japanese stars including Nakai, 17, and Chiba, 20.

From Barron's • Feb. 17, 2026

This is the closest I’ve seen her, and she looks more like a big sister to Ainsley and Darius than their mother.

From "Pride" by Ibi Zoboi