1. a viral disease of cattle causing a mild skin disease affecting the udder; formerly used to inoculate humans against smallpox • Syn: cowpox • Hypernyms: animal disease, pox 2. a local infection induced in humans by inoculation with the virus causing cowpox in order to confer resistance to smallpox; normally lasts three weeks and leaves a pitted scar • Syn: vaccina, variola vaccine, variola vaccinia, variola vaccina • Hypernyms: infection • Hyponyms: progressive vaccinia, vaccinia gangrenosa