Princeton's WordNet

1. vaccinia, vaccina, variola vaccine, variola vaccinia, variola vaccina(noun)

   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

   Synonyms:
   cowpox, vaccina, vaccinia, variola vaccina, variola vaccine, variola vaccinia

2. cowpox, vaccinia(noun)

   a viral disease of cattle causing a mild skin disease affecting the udder; formerly used to inoculate humans against smallpox

   Synonyms:
   cowpox, vaccina, variola vaccina, vaccinia, variola vaccine, variola vaccinia