posthumous birth vs birth

posthumous birth and birth both are nouns.

Word	Noun	Adjective	Verb	Adverb
posthumous birth	Yes	No	No	No
birth	Yes	No	Yes	No

As nouns, birth is a hypernym of posthumous birth; that is, birth is a word with a broader meaning than posthumous birth:

posthumous birth: birth of a child by Caesarean section after the death of the mother
birth: the event of being born

Other hypernyms of posthumous birth include nascence, nascency, nativity.

As nouns, birth is a hypernym of posthumous birth; that is, birth is a word with a broader meaning than posthumous birth:

Other hypernyms of posthumous birth include nascence, nascency, nativity.

posthumous birth (noun)	birth (noun)
birth of a child by Caesarean section after the death of the mother	the event of being born
birth of a child after the father has died	a baby born; an offspring
	the process of giving birth
	the kinship relation of an offspring to the parents
	the time when something begins (especially life)

posthumous birth (verb)	birth (verb)
	cause to be born