stepsister

[step-sis-ter] /ˈstɛpˌsɪs tər/
noun
1.
one's stepfather's or stepmother's daughter by a previous marriage.
Origin
1400-50; late Middle English; see step-, sister
Examples from the web for stepsister
  • Until recently, natural gas was the forgotten stepsister of fuels.
  • She was predeceased by her three siblings and a stepsister.
British Dictionary definitions for stepsister

stepsister

/ˈstɛpˌsɪstə/
noun
1.
a daughter of one's stepmother or stepfather by a union with someone other than one's father or mother respectively