little sister
kid sister AmE informal

I never want to play anything with my little sister.

He wants nothing but the best for his little sister.

She's looked up to him over the years and she'll always be his little sister.

Their first idea was a little sister following her brother.

It was like I had just lost my little sister.

She lived to make me and my little sister happy.

"But my little sister put some boys in with the girls and now I have 14."

What kind of, do you ever tell stories to your little sister?

His little sister was the only person in the world who could make him smile any longer.

She can best be described as the little sister of the group.