also: きょうだい
younger brother and sister
Refers to one's younger siblings collectively, specifically a younger brother and a younger sister. Not used for a single younger sibling.
He takes good care of his younger brother and sister.
People who have younger siblings tend to become patient from a young age.
She has two younger siblings, a brother and a sister.
While their mother is at work, the older brother looks after his younger siblings.
Gikun reading; rare and context-dependent. Normally written 兄弟 or 姉妹.