posthumous birth vs nascency

posthumous birth and nascency both are nouns.

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

As nouns, nascency is a hypernym of posthumous birth; that is, nascency 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
nascency: the event of being born

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

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

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

posthumous birth (noun)	nascency (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