child psychology vs developmental psychology

child psychology and developmental psychology both are nouns.

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

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

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

Other synonyms of child psychology include genetic psychology.

child psychology (noun)	developmental 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