Entry 1 sense Webster, 1913 Pistillation /pĭs'tĭ.lāʹshən/ · Pis·til·la·tion · IPA /ˌpɪs.tɪˈleɪ̯.ʃən/ 01 n. The act of pounding or breaking in a mortar; pestillation. 1. The act of pounding or breaking in a mortar; pestillation.[Obs.]