also: おとむすめ
noun
younger daughter
Refers specifically to a younger daughter, often in contrast to an older daughter (姉娘). The term is somewhat literary or used in formal contexts; in everyday speech, 下の娘 or simply 妹 may be more common.
彼の弟娘はまだ小学生だ。
His younger daughter is still in elementary school.
姉娘は大学生で、弟娘は高校生です。
The older daughter is a university student, and the younger daughter is a high school student.
Compound of 弟 (younger brother, but here used in the sense of 'younger') and 娘 (daughter). The reading おとむすめ is a contraction of おとうとむすめ.