sibling
noun [ C ] formal uk/ˈsɪb.lɪŋ/ us/ˈsɪb.lɪŋ/
C2 兄;弟;姐;妹
a brother or sister
I have four siblings: three brothers and a sister. 我有4个兄弟姐妹：3个兄弟，1个姐姐。
There was great sibling rivalry (= competition) between Peter and his brother. 彼得和他的弟弟之间争斗得很厉害。
See also: sib