sorellastra bedeutet auf Englisch

half sister▼(a female half sibling)
noun
[UK: hɑːf ˈsɪ.stə(r)] [US: ˈhæf ˈsɪ.stər]

stepsister [stepsisters]▼(daughter from the previous marriage of a stepparent)
noun
[UK: ˈstep.sɪ.stə(r)] [US: ˈstep.ˌsɪ.stər]Cinderella had two evil stepsisters. = Cenerentola aveva due sorellastre cattive.