also: きょうだい
older brother and younger sister
Specifically refers to a sibling pair consisting of an older brother and a younger sister. Not used for other sibling combinations.
Ken and Yumi are siblings (he's the older brother, she's the younger sister).
They are an older brother and younger sister; the brother is a university student and the sister is a high school student.
The older brother and younger sister went shopping together.
The brother and sister run a small shop together.
姉弟 is the reverse pairing—older sister and younger brother—so it's easy to mix up with 兄妹, which is older brother and younger sister.
姉妹 means 'sisters' (both female), whereas 兄妹 always refers to a mixed brother-sister pair with the brother older.
兄妹 means an older brother and younger sister, while 弟妹 means a younger brother and younger sister, so learners often mix up which sibling is older.
Used when referring to the pair as a set; there is no standard counter for this exact kinship term.
Standard kanji spelling for 'older brother and younger sister'. The reading きょうだい is a gikun/jukujikun reading.
Gikun (meaning-based) reading. Used in some contexts, but けいまい is the standard reading for this kanji compound.
Compound of 兄 (older brother) and 妹 (younger sister). The reading けいまい is the standard on'yomi reading. The reading きょうだい is a jukujikun (special kanji reading) based on the meaning of 'siblings'.