| 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. |
| big sister n.
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