younger stepsister
Archaic term for a younger step-sister. In modern Japanese, 義理の妹 or まま妹 (ままいもうと) are more common.
The word 継妹 appears in old documents, but it is hardly used today.
Kanji spelling using 継 (step-) and 妹 (younger sister); archaic and rarely used in modern Japanese.
Alternate kanji spelling using 庶 (illegitimate/step-); also archaic and uncommon.
Formed from the old native prefix まま-, denoting a step-relationship, and いも, an old word for a sister or other closely related woman. The spelling 継妹 represents these meanings.