noun
last child; youngest child
Refers to the youngest child in a family, often implying the final child born. Somewhat literary or formal; in casual speech 末っ子 (すえっこ) is more common.
彼は五人兄弟の季子だ。
He is the youngest of five siblings.
季子として甘やかされて育った。
As the last child, I was spoiled growing up.