Entry 1 sense Webster, 1913 Decapitation /dĭk-ăpˌ-ĭt-āsh'-ən/ · De·cap·i·ta·tion · IPA /ˈdi.kæp.əˌteɪ.ʃən/ 01 n. The act of beheading; beheading. 1. The act of beheading; beheading.