stepsister
US /ˈstepˌsɪs.tɚ/
UK /ˈstepˌsɪs.tɚ/

1.
sorellastra
a daughter of one's step-parent by a previous marriage
:
•
My stepsister and I get along really well.
Io e la mia sorellastra andiamo molto d'accordo.
•
She introduced her stepsister to the family.
Ha presentato la sua sorellastra alla famiglia.