兒
ジ, ニ, ゲイ, こ, ちご
child, young of animals
JLPT0 G13 S0 F5000
The relevant seal inscription form shows, as depicted in 思, a profusion of fine bones in fontanels (open spaces in an infant's skull over which the skull bones eventually fuse) + 儿 person → *infant*; (very young) *child*.
[Full Kanji Etymology List]