Meaning

noun a common venereal disease caused by the treponema pallidum spirochete; symptoms change through progressive stages; can be congenital (transmitted through the placenta)

noun a contagious disease characterized by purulent skin eruptions that may leave pock marks

originFrom the plural of Middle English pocke. See also pock. The curse sense involves metonymy: wishing a literal pox upon someone is the original form of pox-relevant curse, and the word pox itself also came to mean curse.

Etymology from Wiktionary, CC BY-SA 3.0