Entry 1 sense Webster, 1913 Vaccinia /vəch-ēn'-ē-ə/ · Vac·cin·i·a · IPA /vətʃˈiːniːə/ 01 n. Cowpox; vaccina. See Cowpox. 1. Cowpox; vaccina. See Cowpox.(Med.) See: Cowpox