表妹 biǎomèi
[a daughter of father's sister or of mother's brother or sister,who is younger than oneself] 姑母、舅舅、姨母的女儿中比自己(说话人)年轻者
称谓。用以称姑妈、姨妈、舅舅的女儿，且年纪比自己小。
英语 younger female cousin via female line
德语 jüngere Cousine (S)
法语 cousine cadette