Entry 1 sense Webster, 1913 Exfoliation /ĕk-sfōlˌ-ē-āsh'-ən/ · Ex·fo·li·a·tion · IPA /ɛksfˌoʊliːˈeɪʃən/ 01 n. The scaling off of a bone, a rock, or a mineral, etc.; the state of being exfoliated. 1. The scaling off of a bone, a rock, or a mineral, etc.; the state of being exfoliated.