half-sister (different father); half-sisters (different father)
Refers specifically to sisters who share the same mother but have different fathers. The term is neutral and factual, used in family or legal contexts.
She is my half-sister (different father).
I have two half-sisters (different father).
異母姉妹 refers to half-sisters sharing the same father but different mothers, the opposite of 異父姉妹.
異父兄弟 is the gender-neutral or male counterpart, meaning half-sibling(s) (different father).
Compound of 異父 (いふ, 'different father') and 姉妹 (しまい, 'sisters'). The kanji 異 means 'different', 父 means 'father', and 姉妹 means 'sisters'.