牛痘苗 niúdòumiáo smallpox vaccine Origin Definitions Defs Strokes Stroke Words Sentences Sents 牛痘 niúdòu smallpox vaccine vaccine material used to provide immunity against smallpox, originally derived from the cowpox virus苗 miáo noun vaccine a biological preparation that provides immunity, such as a vaccine; short for 疫苗 yìmiáo