pox vs primary syphilis

pox and primary syphilis both are nouns.

Word	Noun	Adjective	Verb	Adverb
pox	Yes	No	No	No
primary syphilis	Yes	No	No	No

As nouns, primary syphilis is a hyponym of pox; that is, primary syphilis is a word with a more specific, narrower meaning than pox:

pox: a common venereal disease caused by the treponema pallidum spirochete; symptoms change through progressive stages; can be congenital (transmitted through the placenta)
primary syphilis: the first stage; characterized by a chancre at the site of infection

Other hyponyms of pox include secondary syphilis, tertiary syphilis, neurosyphilis.

pox (noun)	primary syphilis (noun)
a contagious disease characterized by purulent skin eruptions that may leave pock marks	the first stage; characterized by a chancre at the site of infection
a common venereal disease caused by the treponema pallidum spirochete; symptoms change through progressive stages; can be congenital (transmitted through the placenta)