Entry 1 sense Webster, 1913 Allotropic /(ăl`lō̇*trŏp"ĭk)/ · Al·lo·trop·ic · IPA /ˌæləˈtɹɑpɪk/ 01 a. Of or pertaining to allotropism. 1. Of or pertaining to allotropism. Phrases & compounds Allotropic state — the several conditions which occur in a case of allotropism.