Half-sister

Diane is your half-sister too, George.

She's my half-sister.

Mary is Tom's half-sister.

She's my half-sister, but I call her my sister.

Morgan le Fay was a powerful sorceress and the half-sister of King Arthur.

Thomas has a half-sister.

Tom has a half-sister.

Mary is my half-sister.

I have a half-sister.

Tom's half-sister is married to a Czech man and teaches English in Prague, where she also lives.