a contagious viral disease of cows characterized by vesicles on the skin, esp on the teats and udder. Inoculation of humans with this virus provides temporary immunity to smallpox. It can be transmitted to other species, esp cats
cowpox in American English
(ˈkaʊˌpɑks)
noun
a contagious viral disease of cows that causes pustules on the udders: people inoculated with a vaccine containing the virus of cowpox become temporarily immune to smallpox