Source : Webster's Revised Unabridged Dictionary (1913)

Vaccinia \Vac*cin"i*a\, n. [NL. See {Vaccine}.] (Med.)
   Cowpox; vaccina. See {Cowpox}.

Source : WordNet®

vaccinia
     n 1: a local infection induced in humans by innoculation 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}]
     2: a viral disease of cattle causing a mild skin disease
        affecting the udder; formerly used to inoculate humans
        against smallpox [syn: {cowpox}]