Entry 1 sense Webster, 1913 Acetification · A·cet·i·fi·ca·tion · IPA /əˌsiː.tɪ.fɪˈkeɪ.ʃən/ 01 n. The act of making acetous or sour; the process of converting, or of becoming converted, into vinegar. 1. The act of making acetous or sour; the process of converting, or of becoming converted, into vinegar.