pedagogy vs hypnopedia

pedagogy and hypnopedia both are nouns.

Word	Noun	Adjective	Verb	Adverb
pedagogy	Yes	No	No	No
hypnopedia	Yes	No	No	No

As nouns, hypnopedia is a hyponym of pedagogy; that is, hypnopedia is a word with a more specific, narrower meaning than pedagogy:

pedagogy: the profession of a teacher
hypnopedia: teaching during sleep (as by using recordings to teach a foreign language to someone who is asleep)

pedagogy (noun)	hypnopedia (noun)
the profession of a teacher	teaching during sleep (as by using recordings to teach a foreign language to someone who is asleep)
the activities of educating or instructing; activities that impart knowledge or skill
the principles and methods of instruction