Entry 2 senses · 2 variants Webster, 1913 Acetify · A·cet·i·fy · IPA /əˈsiːtɪfaɪ/ v. t. v. i. 01 v. t. To convert into acid or vinegar. imp. & p. p. Acetified; p. pr. & vb. n. Acetifying 1. To convert into acid or vinegar. 02 v. i. To turn acid. 1. To turn acid.