developmental psychology vs child psychology

developmental psychology and child psychology both are nouns.

Word	Noun	Adjective	Verb	Adverb
developmental psychology	Yes	No	No	No
child psychology	Yes	No	No	No

As nouns, developmental psychology and child psychology are synonyms defined as:

developmental psychology and child psychology: the branch of psychology that studies the social and mental development of children

Other synonyms of developmental psychology include genetic psychology.

developmental psychology (noun)	child psychology (noun)
the branch of psychology that studies the social and mental development of children	the branch of psychology that studies the social and mental development of children