Entry 1 sense Webster, 1913 Chicken pox /chĭk'-ən päks/ · Chick·en pox · IPA /ˈt͡ʃɪ.k(ə)nˌpɑks/ 01 A mild, eruptive disease, generally attacking children only; varicella. 1. A mild, eruptive disease, generally attacking children only; varicella.(Med.)