big sister

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.

Example Sentences

These days they joke that Maya will call Kamala “big sister general” until she earns the title of madam president.

From Los Angeles Times

"He has robbed a young boy of his big sister, and caused unimaginable heartache to a loving father and wider family," he said.

From BBC

It likely wouldn't have been great — my mother wasn't great and I doubt another kid would have made her better — but other Mary would have had a big sister to protect her.

From Salon

“Their relationship is interesting, because the second that Olivia is around her big sister in person, she actually acquiesces to her,” Olagundoye says.

From Los Angeles Times

She learned her self-defense and perp-identification skills from her big sister, Carmen, an agent with Homeland Security Investigations who takes a leave to get to the bottom of the attack.

From Los Angeles Times