Noun suffix used in compounds like 男児 (boy), 女児 (girl), 幼児 (infant), or as a standalone noun in formal contexts.
Archaic first-person pronoun used by children when addressing parents or elders. Not used in modern Japanese.
She is the mother of one child.
A boy is playing in the park.
Many infants attend this kindergarten.
A child in the old days would say, 'I will help you, Mother.'
He became the father of two children.
子 is the common standalone noun for 'child', whereas 児 rarely stands alone and instead attaches to other elements to form formal or technical terms.
児 is a person/child term, so it is naturally counted with 人 rather than a thing-counter.
From Middle Chinese 兒 (child). Used as a suffix and in formal compounds; the archaic pronoun usage is a Japanese extension.
problem child
newborn baby; neonate
infants and toddlers; babies and preschool children
young baseball player; high-school baseball player
childcare; day care
stalwart youth; vigorous young man
twins
illegitimate child; child born out of wedlock
keiji; juvenile chum salmon
favorite child; darling child · darling; favorite; star; hero
orphan; child left by the deceased · abandoned child
adventurer in turbulent times; soldier of fortune; one who seizes the moment
infant; baby
retard; moron; cripple
one's dead child
another child; other children
child pornography
boys and girls; children
child; children
children and grandchildren; descendants
mere child's play; trivial matter