Entry 1 sense Webster, 1913 Acephalocystic · A·ceph·a·lo·cys·tic · IPA /eɪˌsɛ.fə.loʊˈsɪ.stɪk/ 01 a. Pertaining to, or resembling, the acephalocysts. 1. Pertaining to, or resembling, the acephalocysts.